Bringing Treasures to the Surface: Previews and Overviews in a Prototype for the Library of Congress National Digital Library - Marchionini,A.S.; Nation,D.; Karasik,S.; Cronnell,T.; Shneiderman, Ben; Spotfire,V.D.M.U.; Bederson, Benjamin B.; Data,T.S.; Hochheiser,H.; Shneiderman, Ben; others (The craft of information visualization: readings and reflections, 2003)

Characterization of a Vibrio cholerae phage isolated from the coastal water of Peru - Talledo,Miguel; Rivera,Irma N. G.; Lipp,Erin K.; Neale,Angela; Karaolis,David; Huq,Anwar; Rita R Colwell (Environmental Microbiology, 2003)
A Vibrio cholerae bacteriophage, family Myoviridae, was isolated from seawater collected from the coastal water of Lima, Peru. Genome size was estimated to be 29 kbp. The temperate phage was specific to V. cholerae and infected 12/13 V. cholerae O1 strains and half of the four non-O1/non-O139 strains tested in this study. Vibrio cholerae O139 strains were resistant to infection and highest infection rates were obtained in low nutrient media amended with NaCl or prepared using seawater as diluent.

Classification-based spatial error concealment for images - Chen,M.; Wu,M.; Zheng,Y. (Image Processing, 2003. ICIP 2003. Proceedings. 2003 International Conference on, 2003)
This paper presents a new, classification-based spatial error concealment algorithm for images. The proposed scheme takes advantage of two state-of-the-art concealment schemes and adaptively selects a better suitable concealment scheme for each corrupted block. Using a support vector machine (SVM) classifier, our proposed approach outperforms the prior art in terms of the concealment quality and has moderate computational complexity.
Keywords: algorithm; classification-based; classification; classifier; complexity; computational; concealment; error; image; Machine; machines; moderate; scheme; spatial; state-of-the-art; Support; SVM; vector

Clustering and Summarizing Medline Abstracts - Dunlavy,Daniel M.; Conroy,John M.; O'Leary,Timothy J; O'Leary, Dianne P. (BISTI 2003 Symposium on Digital Biology: The Emerging ParadigmBISTI 2003 Symposium on Digital Biology: The Emerging Paradigm, 2003)

A collaborative digital library for children - Druin, Allison; Revelle,G.; Bederson, Benjamin B.; Hourcade,J. P; Farber,A.; Lee,J.; Campbell,D. (Journal of Computer Assisted Learning, 2003)

Combining multiple evidences for gait recognition - Cuntoor, N.; Kale, A.; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2003. Proceedings. (ICASSP '03). 2003 IEEE International Conference on, 2003)
In this paper, we systematically analyze different components of human gait, for the purpose of human identification. We investigate dynamic features such as the swing of the hands/legs, the sway of the upper body and static features like height, in both frontal and side views. Both probabilistic and non-probabilistic techniques are used for matching the features. Various combination strategies may be used depending upon the gait features being combined. We discuss three simple rules: the Sum, Product and MIN rules that are relevant to our feature sets. Experiments using four different datasets demonstrate that fusion can be used as an effective strategy in recognition.
Keywords: analysis; dynamic; evidences; extraction; feature; features; frontal; Gait; height; human; identification; image; MIN; multiple; nonprobabilistic; probabilistic; Product; recognition; rules; sets; side; static; Sum; sway; swing; techniques; views

Comparing bootstrap and posterior probability values in the four-taxon case - Cummings, Michael P.; Handley,S. A; Myers,D. S; Reed,D. L; Rokas,A.; Winka,K. (Syst Biol, 2003)
Assessment of the reliability of a given phylogenetic hypothesis is an important step in phylogenetic analysis. Historically, the nonparametric bootstrap procedure has been the most frequently used method for assessing the support for specific phylogenetic relationships. The recent employment of Bayesian methods for phylogenetic inference problems has resulted in clade support being expressed in terms of posterior probabilities. We used simulated data and the four-taxon case to explore the relationship between nonparametric bootstrap values (as inferred by maximum likelihood) and posterior probabilities (as inferred by Bayesian analysis). The results suggest a complex association between the two measures. Three general regions of tree space can be identified: (1) the neutral zone, where differences between mean bootstrap and mean posterior probability values are not significant, (2) near the two-branch corner, and (3) deep in the two-branch corner. In the last two regions, significant differences occur between mean bootstrap and mean posterior probability values. Whether bootstrap or posterior probability values are higher depends on the data in support of alternative topologies. Examination of star topologies revealed that both bootstrap and posterior probability values differ significantly from theoretical expectations; in particular, there are more posterior probability values in the range 0.85-1 than expected by theory. Therefore, our results corroborate the findings of others that posterior probability values are excessively high. Our results also suggest that extrapolations from single topology branch-length studies are unlikely to provide any general conclusions regarding the relationship between bootstrap and posterior probability values.

Deno: a decentralized, peer-to-peer object-replication system for weakly connected environments - Cetintemel,U.; Keleher,P. J; Bhattacharjee, Bobby; Franklin,M.J. (Computers, IEEE Transactions on, 2003)
This paper presents the design, implementation, and evaluation of the replication framework of Deno, a decentralized, peer-to-peer object-replication system targeted for weakly connected environments. Deno uses weighted voting for availability and pair-wise, epidemic information flow for flexibility. This combination allows the protocols to operate with less than full connectivity, to easily adapt to changes in group membership, and to make few assumptions about the underlying network topology. We present two versions of Deno's protocol that differ in the consistency levels they support. We also propose security extensions to handle a class of malicious actions that involve misrepresentation of protocol information. Deno has been implemented and runs on top of Linux and Win32 platforms. We use the Deno prototype to characterize the performance of the Deno protocols and extensions. Our study reveals several interesting results that provide fundamental insight into the benefits of decentralization and the mechanics of epidemic protocols.
Keywords: actions; connected; consistency; data; data; databases; decentralized; Deno; distributed; environments; epidemic; group; levels; Linux; malicious; management; membership; network; object; object-replication; of; operating; peer-to-peer; protocols; replicated; replication; Security; security; synchronisation; system; systems; topology; Unix; voting; weakly; weighted; Win32

Digital Government-Bistro: A Scalable and Secure Data Transfer Service for Digital Government Applications - Golubchik,L.; Cheng,W. C; Chou,C. F; Khuller, Samir; Samet, Hanan; Wan,Y. C.J (Communications of the ACM-Association for Computing Machinery-CACM, 2003)

Direct Detection of Vibrio Cholerae and ctxA in Peruvian Coastal Water and Plankton by PCR - Lipp,Erin K.; Rivera,Irma N. G.; Gil,Ana I.; Espeland,Eric M.; Choopun,Nipa; Louis,Valérie R.; Russek-Cohen,Estelle; Huq,Anwar; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2003)
Seawater and plankton samples were collected over a period of 17 months from November 1998 to March 2000 along the coast of Peru. Total DNA was extracted from water and from plankton grouped by size into two fractions (64 μm to 202 μm and >202 μm). All samples were assayed for Vibrio cholerae, V. cholerae O1, V. cholerae O139, and ctxA by PCR. Of 50 samples collected and tested, 33 (66.0%) were positive for V. cholerae in at least one of the three fractions. Of these, 62.5% (n = 32) contained V. cholerae O1; ctxA was detected in 25% (n = 20) of the V. cholerae O1-positive samples. None were positive for V. cholerae O139. Thus, PCR was successfully employed in detecting toxigenic V. cholerae directly in seawater and plankton samples and provides evidence for an environmental reservoir for this pathogen in Peruvian coastal waters.

Driving scientific applications by data in distributed environments - Saltz, J.; Catalyurek,U.; Kurc, T.; Gray,M.; Hastings,S.; Langella,S.; Narayanan,S.; Martino,R.; Bryant,S.; Peszynska,M.; others (Computational Science—ICCS 2003, 2003)

Effect of treatment on the dynamics of circulating hypodermin C in cattle naturally infested with Hypoderma lineatum (Diptera: Oestridae) - Douglas D Colwell; Panadero-Fontan,Rosario; López-Sandez,Ceferino; Parra-Fernandez,Francisco; Paz-Silva,A; Sánchez-Andrade,Rita; Dı́ez-Baños,Pablo (Veterinary Parasitology, 2003)
An antigen capture ELISA, using a murine monoclonal antibody recognising recombinant hypodermin C (rHyC), was used to evaluate the influence of early treatment with eprinomectin (Eprinex®) or fenthion (Spotton®) on the kinetics of circulating hypodermin C in calves naturally infested with Hypoderma lineatum. No viable larvae were collected from treated animals, whereas a variable number of warbles were found in control animals. Treatment provoked a decrease in circulating HyC levels that was significant 9 days post-treatment (p.t.). Circulating antigen levels in the treated cattle remained detectable for approximately 99 days p.t. In contrast, control animals had no detectable antigen at 64 days p.t., 42 days earlier than in the treated animals. These results suggest that larvae were either gradually killed, resulting in slow release of antigen or they were encapsulated, leading to the slow liberation of antigen. Kinetics of circulating HyC did not differ among the two insecticide treatments. Antibodies persisted, in all groups, throughout the 120-day study. These results suggest that the antigen capture ELISA will be useful as a technique for detecting successful treatment of cattle grub infestations and for the detection of new infestations in previously infested cattle.
Keywords: Capture ELISA; Cattle-arthropoda; Control methods-arthropoda; Eprinomectin; Fenthion; Hypoderma spp.

Effectiveness of conservation targets in capturing genetic diversity - Neel,M. C; Cummings, Michael P. (Conserv Biol, 2003)
Any conservation actions that preserve some populations and not others will have genetic consequences. We used empirical data from four rare plant taxa to assess these consequences in terms of how well allele numbers ( all alleles and alleles occurring at a frequency openface>0.05 in any population ) and expected heterozygosity are represented when different numbers of populations are conserved. We determined sampling distributions for these three measures of genetic diversity using Monte Carlo methods. We assessed the proportion of alleles included in the number of populations considered adequate for conservation, needed to capture all alleles, and needed to meet an accepted standard of genetic-diversity conservation of having a 90-95% probability of including all common alleles. We also assessed the number of populations necessary to obtain values of heterozygosity within +/-10% of the value obtained from all populations. Numbers of alleles were strongly affected by the number of populations sampled. Heterozygosity was only slightly less sensitive to numbers of populations than were alleles. On average, currently advocated conservation intensities represented 67-83% of all alleles and 85-93% of common alleles. The smallest number of populations to include all alleles ranged from 6 to 17 ( 42-57% ), but <0.2% of 1000 samples of these numbers of populations included them all. It was necessary to conserve 16-29 ( 53-93% ) of the sampled populations to meet the standard for common alleles. Between 20% and 64% of populations were needed to reliably represent species-level heterozygosity. Thus, higher percentages of populations are needed than are currently considered adequate to conserve genetic diversity if populations are selected without genetic data.

Efficient dissemination of aggregate data over the wireless web - Sharaf,M. A; Sismanis,Y.; Labrinidis,A.; Chrysanthis,P.; Roussopoulos, Nick (International Workshop on the Web and Databases (WebDB), 2003)

Efficient peer-to-peer searches using result-caching - Bhattacharjee, Bobby; Chawathe,S.; Gopalakrishnan,V.; Keleher,P.; Silaghi,B. (Peer-to-Peer Systems II, 2003)
Existing peer-to-peer systems implement a single function well: data lookup. There is now a wealth of research describing how to reliably disseminate, and to later retrieve, data in a scalable and load-balanced manner.

Eight lessons learned during COTS-based systems maintenance - Reifer,D.J.; Basili, Victor R.; Boehm,B.W.; Clark,B. (Software, IEEE, 2003)
To make better decisions relative to CBSs, we need empirical knowledge. To gain this knowledge, we must more fully understand the lifecycle processes people use when harnessing COTS packages. The initial findings reported here are but the first step in our attempts to capture this empirical knowledge. We plan to continue collecting data and investigating the phenomenology of COTS-based systems.
Keywords: COTS; COTS-based; cycle; life; lifecycle; Maintenance; maintenance; object-oriented; packages; phase; processes; programming; reusability; software; systems

Emergence and Evolution of Vibrio Cholerae O139 - Faruque,Shah M.; Sack,David A.; Sack,R. Bradley; Rita R Colwell; Takeda,Yoshifumi; Nair,G. Balakrish (Proceedings of the National Academy of SciencesPNAS, 2003)
The emergence of Vibrio cholerae O139 Bengal during 1992–1993 was associated with large epidemics of cholera in India and Bangladesh and, initially, with a total displacement of the existing V. cholerae O1 strains. However, the O1 strains reemerged in 1994 and initiated a series of disappearance and reemergence of either of the two serogroups that was associated with temporal genetic and phenotypic changes sustained by the strains. Since the initial emergence of the O139 vibrios, new variants of the pathogen derived from multiple progenitors have been isolated and characterized. The clinical and epidemiological characteristics of these strains have been studied. Rapid genetic reassortment in O139 strains appears to be a response to the changing epidemiology of V. cholerae O1 and also a strategy for persistence in competition with strains of the O1 serogroup. The emergence of V. cholerae O139 has provided a unique opportunity to witness genetic changes in V. cholerae that may be associated with displacement of an existing serogroup by a newly emerging one and, thus, provide new insights into the epidemiology of cholera. The genetic changes and natural selection involving both environmental and host factors are likely to influence profoundly the genetics, epidemiology, and evolution of toxigenic V. cholerae, not only in the Ganges Delta region of India and Bangladesh, but also in other areas of endemic and epidemic cholera.

An experimental evaluation of correlated network partitions in the Coda distributed file system - Lefever,R.M.; Michel Cukier; Sanders,W. H. (2003)
Experimental evaluation is an important way to assess distributed systems, and fault injection is the dominant technique in this area for the evaluation of a system's dependability. For distributed systems, network failure is an important fault model. Physical network failures often have far-reaching effects, giving rise to multiple correlated failures as seen by higher-level protocols. This paper presents an experimental evaluation, using the Loki fault injector, which provides insight into the impact that correlated network partitions have on the Coda distributed file system. In this evaluation, Loki created a network partition between two Coda file servers, during which updates were made at each server to the same replicated data volume. Upon repair of the partition, a client requested directory resolution to converge the diverging replicas. At various stages of the resolution, Loki invoked a second correlated network partition, thus allowing us to evaluate its impact on the system's correctness, performance, and availability.
Keywords: client-server systems; Coda distributed file system; correlated network partitions; distributed file systems; experimental evaluation; fault model; Loki fault injector; multiple correlated failures; network failure; Network topology; performance evaluation; replicated data; replicated databases; software fault tolerance; system performance evaluation

Face recognition: A literature survey - Zhao, W.; Chellapa, Rama; Phillips,P.J.; Rosenfeld, A. (ACM Comput. Surv., 2003)
As one of the most successful applications of image analysis and understanding, face recognition has recently received significant attention, especially during the past several years. At least two reasons account for this trend: the first is the wide range of commercial and law enforcement applications, and the second is the availability of feasible technologies after 30 years of research. Even though current machine recognition systems have reached a certain level of maturity, their success is limited by the conditions imposed by many real applications. For example, recognition of face images acquired in an outdoor environment with changes in illumination and/or pose remains a largely unsolved problem. In other words, current systems are still far away from the capability of the human perception system.This paper provides an up-to-date critical survey of still- and video-based face recognition research. There are two underlying motivations for us to write this survey paper: the first is to provide an up-to-date review of the existing literature, and the second is to offer some insights into the studies of machine recognition of faces. To provide a comprehensive survey, we not only categorize existing recognition techniques but also present detailed descriptions of representative methods within each category. In addition, relevant topics such as psychophysical studies, system evaluation, and issues of illumination and pose variation are covered.
Keywords: face recognition; person identification

Face reconstruction from monocular video using uncertainty analysis and a generic model - Roy Chowdhury,Amit K.; Chellapa, Rama (Computer Vision and Image Understanding, 2003)
Reconstructing a 3D model of a human face from a monocular video sequence is an important problem in computer vision, with applications to recognition, surveillance, multimedia, etc. However, the quality of 3D reconstructions using structure from motion (SfM) algorithms is often not satisfactory. One of the reasons is the poor quality of the input video data. Hence, it is important that 3D face reconstruction algorithms take into account the statistics representing the quality of the video. Also, because of the structural similarities of most faces, it is natural that the performance of these algorithms can be improved by using a generic model of a face. Most of the existing work using this approach initializes the reconstruction algorithm with this generic model. The problem with this approach is that the algorithm can converge to a solution very close to this initial value, resulting in a reconstruction which resembles the generic model rather than the particular face in the video which needs to be modeled. In this paper, we propose a method of 3D reconstruction of a human face from video in which the 3D reconstruction algorithm and the generic model are handled separately. We show that it is possible to obtain a reasonably good 3D SfM estimate purely from the video sequence, provided the quality of the input video is statistically assessed and incorporated into the algorithm. The final 3D model is obtained after combining the SfM estimate and the generic model using an energy function that corrects for the errors in the estimate by comparing the local regions in the two models. The main advantage of our algorithm over others is that it is able to retain the specific features of the face in the video sequence even when these features are different from those of the generic model and it does so even as the quality of the input video varies. The evolution of the 3D model through the various stages of the algorithm and an analysis of its accuracy are presented.
Keywords: Energy function minimization; Face modeling; Generic model; stochastic approximation; structure from motion; uncertainty analysis

A Factorization Approach for Activity Recognition - Chowdhury,Amit K. Roy; Chellapa, Rama (Computer Vision and Pattern Recognition Workshop, 2003. CVPRW '03. Conference on, 2003)
Understanding activities arising out of the interactions of a configuration of moving objects is an important problem in video understanding, with applications in surveillance and monitoring. A special situation is when the objects are small enough to be represented as points on a 2D plane. In this paper, we introduce a novel method of representing the activity by the deformations of the point configuration in a properly defined shape space. Instead of inferring about the activity directly from the motion tracks of the individual points, we propose to model an activity by the polygonal shape formed by joining the locations of these point masses at any time t, and its deformation as the activity unfolds. Given the locations of the 2D points over a sequence of frames in the video, the factorization theorem for matrices is used to obtain a set of basis shapes for each activity. An unknown activity can now be recognized by projecting onto these basis shapes. Also, once a specific activity is recognized, the deviations from it can be modeled by the deformations from the basis shape. This is used to identify an abnormal activity. We demonstrate the applicability of our algorithm using real-life video sequences in an airport surveillance environment. We are able to identify the major activities that take place in that setting and detect abnormal ones.

Fast two-frame multiscale dense optical flow estimation using discrete wavelet filters - Liu,Haiying; Chellapa, Rama; Rosenfeld,Azriel (Journal of the Optical Society of America AJ. Opt. Soc. Am. A, 2003)
A multiscale algorithm with complexity O(N) (where N is the number of pixels in one image) using wavelet filters is proposed to estimate dense optical flow from two frames. Hierarchical image representation by wavelet decomposition is integrated with differential techniques in a new multiscale framework. It is shown that if a compactly supported wavelet basis with one vanishing moment is carefully selected, hierarchical image, first-order derivative, and corner representations can be obtained from the wavelet decomposition. On the basis of this result, three of the four components of the wavelet decomposition are employed to estimate dense optical flow with use of only two frames. This overcomes the “flattening-out” problem in traditional pyramid methods, which produce large errors when low-texture regions become flat at coarse levels as a result of blurring. A two-dimensional affine motion model is used to formulate the optical flow problem as a linear system, with all resolutions simultaneously (i.e., coarse-and-fine) rather than the traditional coarse-to-fine approach, which unavoidably propagates errors from the coarse level. This not only helps to improve the accuracy but also makes the hardware implementation of our algorithm simple. Experiments on different types of image sequences, together with quantitative and qualitative comparisons with several other optical flow methods, are given to demonstrate the effectiveness and the robustness of our algorithm.
Keywords: digital image processing; Image analysis; optical flow

Footloose: a case for physical eventual consistency and selective conflict resolution - Paluska; Saff; Yeh; Chen (Mobile Computing Systems and Applications, 2003. Proceedings. Fifth IEEE Workshop on, 2003)
Users are increasingly inundated with small devices with communication and storage capabilities. Unfortunately, the user is still responsible for reconciling all of the devices whenever a change is made. We present Footloose, a user-centered data store that can share data and reconcile conflicts across diverse devices. Footloose is an optimistic system based on physical eventual consistency: consistency based on the movement of devices, and selective conflict resolution, which allows conflicts to flow through devices that cannot resolve the conflict to devices that can. Using these techniques, Footloose can present consistent views of data on the devices closest to the user without user interaction.

Formal verification of an intrusion-tolerant group membership protocol - Ramasamy,H. V.; Michel Cukier; Sanders,W. H. (IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS E SERIES D, 2003)
The traditional approach for establishing thecorrectness of group communication protocols is through rigor- ous arguments. While this is a valid approach, the likelihood of subtle errors in the design and implementation of such complex distributed protocols is not negligible. The use of formal verifi- cation methods has been widely advocated to instill confidence in the correctness of protocols. In this paper, we describe how we used the SPIN model checker to formally verify a group mem- bership protocol that is part of an intrusion-tolerant group com- munication system. We describe how we successfully tackled the state-space explosion problem by determining the right abstrac- tion level for formally specifying the protocol. The verification exercise not only formally showed that the protocol satisfies its correctness claims, but also provided information that will help us make the protocol more efficient without violating correctness. key words: intrusion tolerance, group communication systems, validation, formal methods

A forward-secure public-key encryption scheme - Canetti,R.; Halevi,S.; Katz, Jonathan (Advances in Cryptology—Eurocrypt 2003, 2003)
Cryptographic computations are often carried out on insecure devices for which the threat of key exposure represents a serious and realistic concern. In an effort to mitigate the damage caused by exposure of secret data (e.g., keys) stored on such devices, the paradigm of forward security was introduced. In a forward-secure scheme, secret keys are updated at regular periods of time; furthermore, exposure of a secret key corresponding to a given time period does not enable an adversary to “break” the scheme (in the appropriate sense) for any prior time period. A number of constructions of forward-secure digital signature schemes, key-exchange protocols, and symmetric-key schemes are known.We present the first constructions of a (non-interactive) forward-secure public-key encryption scheme. Our main construction achieves security against chosen plaintext attacks under the decisional bilinear Diffie-Hellman assumption in the standard model. It is practical, and all complexity parameters grow at most logarithmically with the total number of time periods. The scheme can also be extended to achieve security against chosen ciphertext attacks.

From terabytes to insights - Rita R Colwell (Communications of the ACM, 2003)
For scientists and engineers tapping the NSF's high-performance cyberinfrastructure, the path to wisdom follows a route both miraculous and familiar.

Gait Analysis for Human Identification - Kale, A.; Cuntoor, N.; Yegnanarayana,B.; Rajagopalan, AN; Chellapa, Rama (Audio- and Video-Based Biometric Person AuthenticationAudio- and Video-Based Biometric Person Authentication, 2003)
Human gait is an attractive modality for recognizing people at a distance. In this paper we adopt an appearance-based approach to the problem of gait recognition. The width of the outer contour of the binarized silhouette of a walking person is chosen as the basic image feature. Different gait features are extracted from the width vector such as the dowsampled, smoothed width vectors, the velocity profile etc. and sequences of such temporally ordered feature vectors are used for representing a person’s gait. We use the dynamic time-warping (DTW) approach for matching so that non-linear time normalization may be used to deal with the naturally-occuring changes in walking speed. The performance of the proposed method is tested using different gait databases.

Genetic consequences of ecological reserve design guidelines: An empirical investigation - Neel,M. C; Cummings, Michael P. (Conserv Genet, 2003)
We assessed the genetic diversity consequences of applying ecological reserve design guidelines to four federally-listed globally-rare plant species. Consequences were measured using two metrics: proportion of all alleles and of common alleles included in reserves. Common alleles were defined as those alleles having a frequency of greater than or equal to0.05 in at least one population. Four conservation professionals applied ecological reserve guidelines to choose specific populations of each species for inclusion in reserves of size 1 to N - 1, where N is the total number of populations of each species. Information regarding genetic diversity was not used in selecting populations. The resulting reserve designs were compared to random designs, and the agreement among experts was assessed using Kendall's coefficient of concordance. Application of ecological reserve design guidelines proved mostly ineffective in capturing more genetic diversity than is captured selecting populations randomly. Meeting established targets for genetic diversity, such as one advocated by the Center for Plant Conservation, required larger numbers of populations than are suggested to be sufficient. Relative performance of expert designs differed among species and was dependent on whether the proportion of all alleles or of common alleles was used as a measure of diversity. Furthermore there was no significant concordance among experts in order in which populations were incorporated into reserves as experts differed in priority they placed on individual guidelines.
Keywords: albens; Astragulus; Bernardino; conservation; conservation; design; diversity; Erigeron; Eriogonum; genetic; genetics; goodmaniana; Mountains; ovalifolium; Oxytheca; parishii; parishii; plant; reserve; San; var.; vineum

The genome sequence of Bacillus anthracis Ames and comparison to closely related bacteria - Read,Timothy D.; Peterson,Scott N.; Tourasse,Nicolas; Baillie,Les W.; Paulsen,Ian T.; Nelson,Karen E.; Tettelin,Herv|[eacute]|; Fouts,Derrick E.; Eisen,Jonathan A.; Gill,Steven R.; Holtzapple,Erik K.; |[Oslash]|kstad,Ole Andreas; et al. (Nature, 2003)
Bacillus anthracis is an endospore-forming bacterium that causes inhalational anthrax1. Key virulence genes are found on plasmids (extra-chromosomal, circular, double-stranded DNA molecules) pXO1 (ref. 2) and pXO2 (ref. 3). To identify additional genes that might contribute to virulence, we analysed the complete sequence of the chromosome of B. anthracis Ames (about 5.23 megabases). We found several chromosomally encoded proteins that may contribute to pathogenicity—including haemolysins, phospholipases and iron acquisition functions—and identified numerous surface proteins that might be important targets for vaccines and drugs. Almost all these putative chromosomal virulence and surface proteins have homologues in Bacillus cereus, highlighting the similarity of B. anthracis to near-neighbours that are not associated with anthrax4. By performing a comparative genome hybridization of 19 B. cereus and Bacillus thuringiensis strains against a B. anthracis DNA microarray, we confirmed the general similarity of chromosomal genes among this group of close relatives. However, we found that the gene sequences of pXO1 and pXO2 were more variable between strains, suggesting plasmid mobility in the group. The complete sequence of B. anthracis is a step towards a better understanding of anthrax pathogenesis.

HCIL Technical Report Listing (1993-2002) - Ceaparu,I.; Druin, Allison; Guimbretiere,F.; Manipulation,D.; Shneiderman, Ben; Westerlurid,B.; Keogh,E.; Hochheiser,H.; Shrieidemian,B.; Shneidemiari,B.; others (The craft of information visualization: readings and reflections, 2003)

Help! I’m lost: User frustration in web navigation - Lazar,J.; Bessiere,K.; Ceaparu,I.; Robinson,J.; Shneiderman, Ben (IT & Society, 2003)
Computers can be valuable tools, and networked resources via the Internet can be beneficial to many different populations and communities. Unfortunately, when people are unable to reach their task goals due to frustrating experiences, this can hinder the effectiveness of technology. This research summary provides information about the user frustration research that has been performed at the University of Maryland and Towson University. Causes of user frustration are discussed in this research summary, along with the surprising finding that nearly one-third to one-half of the time spent in front of the computer is wasted due to frustrating experiences. Furthermore, when interfaces are planned to be deceptive and confusing, this can lead to increased frustration. Implications for designers and users are discussed.

A hidden Markov model based framework for recognition of humans from gait sequences - Sundaresan,Aravind; RoyChowdhury,Amit; Chellapa, Rama (Image Processing, 2003. ICIP 2003. Proceedings. 2003 International Conference on, 2003)
In this paper we propose a generic framework based on hidden Markov models (HMMs) for recognition of individuals from their gait. The HMM framework is suitable, because the gait of an individual can be visualized as his adopting postures from a set, in a sequence which has an underlying structured probabilistic nature. The postures that the individual adopts can be regarded as the states of the HMM and are typical to that individual and provide a means of discrimination. The framework assumes that, during gait, the individual transitions between N discrete postures or states but it is not dependent on the particular feature vector used to represent the gait information contained in the postures. The framework, thus, provides flexibility in the selection of the feature vector. The statistical nature of the HMM lends robustness to the model. In this paper we use the binarized background-subtracted image as the feature vector and use different distance metrics, such as those based on the L1 and L2 norms of the vector difference, and the normalized inner product of the vectors, to measure the similarity between feature vectors. The results we obtain are better than the baseline recognition rates reported before.
Keywords: analysis; background-subtracted; binarized; discrete; distance; feature; Gait; hidden; human; image; image; Markov; metrics; model; models; postures; recognition; sequences; vector

Innovating the Interaction - Bederson, Benjamin B.; Plaisant, Catherine; Mushlin,R.; Snyder,A.; Li,J.; Heller,D.; Shneiderman, Ben; Hochheiser,H.; Fekete,J. D; Czenvinski,M. (The craft of information visualization: readings and reflectionsThe craft of information visualization: readings and reflections, 2003)

The integrated CWB-NC/PIOAtool for functional verification and performance analysis of concurrent systems - Zhang,D.; Cleaveland, Rance; Stark,E. W (Proceedings of the 9th international conference on Tools and algorithms for the construction and analysis of systems, 2003)

Interactive color mosaic and dendrogram displays for signal/noise optimization in microarray data analysis - Seo,J.; Bakay,M.; Zhao,P.; Chen,Y.W.; Clarkson,P.; Shneiderman, Ben; Hoffman,E.P. (Multimedia and Expo, 2003. ICME'03. Proceedings. 2003 International Conference on, 2003)
Data analysis and visualization is strongly influenced by noise and noise filters. There are multiple sources of oisein microarray data analysis, but signal/noise ratios are rarely optimized, or even considered. Here, we report a noise analysis of a novel 13 million oligonucleotide dataset - 25 human U133A (~500,000 features) profiles of patient muscle biposies. We use our recently described interactive visualization tool, the Hierarchical Clustering Explorer (HCE) to systemically address the effect of different noise filters on resolution of arrays into orrectbiological groups (unsupervised clustering into three patient groups of known diagnosis). We varied probe set interpretation methods (MAS 5.0, RMA), resent callfilters, and clustering linkage methods, and investigated the results in HCE. HCE interactive features enabled us to quickly see the impact of these three variables. Dendrogram displays showed the clustering results systematically, and color mosaic displays provided a visual support for the results. We show that each of these three variables has a strong effect on unsupervised clustering. For this dataset, the strength of the biological variable was maximized, and noise minimized, using MAS 5.0, 10% present call filter, and Average Group Linkage. We propose a general method of using interactive tools to identify the optimal signal/noise balance or the optimal combination of these three variables to maximize the effect of the desired biological variable on data interpretation.

Interactive Visualization of Large Tetrahedral Meshes through Selective Refinement - Cignoni,P.; De Floriani, Leila; Magillo,P.; Puppo,E.; Scopigno,R.; di Genova,U. (IEEE Transactions on Visualization and Computer Graphics, 2003)
In this paper, we address the problem of the efficient visualization of very largeirregular volume datasets. To this aim, we exploit a multiresolution representation based on a domain decomposition into tetrahedral cells. A new compact data struc- ture is described which encodes the whole dataset at a virtually continuous range of different resolutions, with a storage cost six times lower than a standard data struc- ture for tetrahedral meshes. Such structure supports on-line selective refinement to focus resolution on areas that the user considers more critical, based on either field values, or domain location, or opacity of the transfer function. Selective refinement is used to trade-off between resolution and speed in visualization, according to user needs and hardware constraints. These features have been implemented in a new system, called TAn2 (Tetrahedra Analyzer), for the interactive visualization of three- dimensional scalar fields defined on very large tetrahedral meshes. Multiresolution representation and selective refinement make the system fully scalable with respect to the size of the dataset and to hardware requirements.

Machine and Human Performance for Single- and Multi-Document Summarization - Schlesinger,Judith D.; Conroy,John M.; Okurowski,Mary Ellen; O'Leary, Dianne P. (IEEE Intelligent Systems (special issue on Natural Language Processing), 2003)

Method of DNA extraction and application of multiplex polymerase chain reaction to detect toxigenic Vibrio cholerae O1 and O139 from aquatic ecosystems - Rivera,Irma N. G.; Lipp,Erin K.; Gil,Ana; Choopun,Nipa; Huq,Anwar; Rita R Colwell (Environmental Microbiology, 2003)
Vibrio cholerae is a free-living bacterium found in water and in association with plankton. V. cholerae non-O1/non-O139 strains are frequently isolated from aquatic ecosystems worldwide. Less frequently isolated are V. cholerae O1 and V. cholerae O139, the aetiological agents of cholera. These strains have two main virulence-associated factors, cholera toxin (CT) and toxin co-regulated pilus (TCP). By extracting total DNA from aquatic samples, the presence of pathogenic strains can be determined quickly and used to improve a microbiological risk assessment for cholera in coastal areas. Some methods suggested for DNA extraction from water samples are not applicable to all water types. We describe here a method for DNA extraction from coastal water and a multiplex polymerase chain reaction (PCR) for O1 and O139 serogroups. DNA extraction was successfully accomplished from 117 sea water samples collected from coastal areas of Perú, Brazil and the USA. DNA concentration in all samples varied from 20 ng to 480 µg µl−1. The sensitivity of the DNA extraction method was 100 V. cholerae cells in 250 ml of water. The specificity of multiplex O1/O139 PCR was investigated by analysing 120 strains of V. cholerae, Vibrio and other Bacteria species. All V. cholerae O1 and O139 tested were positive. For cholera surveillance of aquatic environments and ballast water, total DNA extraction, followed by V. cholerae PCR, and O1/O139 serogroup and tcpA/ctxA genes by multiplex PCR offers an efficient system, permitting risk analysis for cholera in coastal areas.

Necessity is the mother of invention: a simple grid computing system using commodity tools - Myers,D. S; Cummings, Michael P. (J Parallel Distr Com, 2003)
Access to sufficient resources is a barrier to scientific progress for many researchers facing large computational problems. Gaining access to large-scale resources (i.e., university-wide or federally supported computer centers) can be difficult, given their limited availability, particular architectures, and request/review/approval cycles. Simultaneously, researchers often find themselves with access to workstations and older clusters overlooked by their owners in favor of newer hardware. Software to tie these resources into a coherent Grid, however, has been problematic. Here, we describe our experiences building a Grid computing system to conduct a large-scale simulation study using "borrowed" computing resources distributed over a wide area. Using standard software components, we have produced a Grid computing system capable of coupling several hundred processors spanning multiple continents and administrative domains. We believe that this system fills an important niche between a closely coupled local system and a heavyweight, highly customized wide area system. (C) 2003 Elsevier Science (USA). All rights reserved.
Keywords: Apache; computing; distributed; Grid; HTTP; Java; Linux; Perl; SQL; Unix; XML-RPC

A particle filtering approach to abnormality detection in nonlinear systems and its application to abnormal activity detection - Vaswani, N.; Chellapa, Rama (3rd Int’l Workshop on Statistical and Computational Theories of Vision, Nice, France, 2003)
We study abnormality detection in partially observed nonlinear dynamic systems tracked usingparticle filters. An ‘abnormality’ is defined as a change in the system model, which could be drastic or gradual, with the parameters of the changed system unknown. If the change is drastic the particle filter will lose track rapidly and the increase in tracking error can be used to detect the change. In this paper we propose a new statistic for detecting ‘slow’ changes or abnormalities which do not cause the particle filter to lose track for a long time. In a previous work, we have proposed a partially observed nonlinear dynamical system for modeling the configuration dynamics of a group of interacting point objects and formulated abnormal activity detection as a change detection problem. We show here results for abnormal activity detection comparing our proposed change detection strategy with others used in literature.

Pathogenic Potential of Environmental Vibrio Cholerae Strains Carrying Genetic Variants of the Toxin-Coregulated Pilus Pathogenicity Island - Faruque,Shah M.; Kamruzzaman,M.; Meraj,Ismail M.; Chowdhury,Nityananda; Nair,G. Balakrish; Sack,R. Bradley; Rita R Colwell; Sack,David A. (Infection and ImmunityInfect. Immun., 2003)
The major virulence factors of toxigenic Vibrio cholerae are cholera toxin (CT), which is encoded by a lysogenic bacteriophage (CTXΦ), and toxin-coregulated pilus (TCP), an essential colonization factor which is also the receptor for CTXΦ. The genes for the biosynthesis of TCP are part of a larger genetic element known as the TCP pathogenicity island. To assess their pathogenic potential, we analyzed environmental strains of V. cholerae carrying genetic variants of the TCP pathogenicity island for colonization of infant mice, susceptibility to CTXΦ, and diarrheagenicity in adult rabbits. Analysis of 14 environmental strains, including 3 strains carrying a new allele of the tcpA gene, 9 strains carrying a new allele of the toxT gene, and 2 strains carrying conventional tcpA and toxT genes, showed that all strains colonized infant mice with various efficiencies in competition with a control El Tor biotype strain of V. cholerae O1. Five of the 14 strains were susceptible to CTXΦ, and these transductants produced CT and caused diarrhea in adult rabbits. These results suggested that the new alleles of the tcpA and toxT genes found in environmental strains of V. cholerae encode biologically active gene products. Detection of functional homologs of the TCP island genes in environmental strains may have implications for understanding the origin and evolution of virulence genes of V. cholerae.

Performance of a Three-Stage System for Multi-Document Summarization - Dunlavy,Daniel M.; Conroy,John M.; Schlesinger,Judith D.; Goodman,Sarah A.; Okurowski,Mary Ellen; O'Leary, Dianne P.; Halteren,Hans van (DUC 03 Conference ProceedingsDUC 03 Conference Proceedings, 2003)

Persistence of adhesive properties in Vibrio cholerae after long‐term exposure to sea water - Pruzzo,Carla; Tarsi,Renato; Del Mar Lleò,Maria; Signoretto,Caterina; Zampini,Massimiliano; Pane,Luigi; Rita R Colwell; Canepari,Pietro (Environmental Microbiology, 2003)
The effect of exposure to artificial sea water (ASW) on the ability of classical Vibrio cholerae O1 cells to interact with chitin-containing substrates and human intestinal cells was studied. Incubation of vibrios in ASW at 5°C and 18°C resulted in two kinds of cell responses: the viable but non-culturable (VBNC) state (i.e. <0.1 colony forming unit ml−1) at 5°C, and starvation (i.e. maintenance of culturability of the population) at 18°C. The latter remained rod shaped and, after 40 days’ incubation, presented a 47–58% reduction in the number of cells attached to chitin, a 48–53% reduction in the number of bacteria adhering to copepods, and a 48–54% reduction in the number of bacteria adhering to human cultured intestinal cells, compared to control cells not suspended in ASW. Bacteria suspended in ASW at 5°C became coccoid and, after 40 days, showed 34–42% fewer cells attached to chitin, 52–55% fewer adhering to copep-ods, and 45–48% fewer cells adhering to intestinal cell monolayers, compared to controls. Sarkosyl-insoluble membrane proteins that bind chitin particles were isolated and analysed by SDS-PAGE. After 40 days incubation in ASW at both 5°C and 18°C vibrios expressed chitin-binding ligands similar to bacteria harvested in the stationary growth phase. It is concluded that as vibrios do not lose adhesive properties after long-term exposure to ASW, it is important to include methods for VBNC bacteria when testing environmental and clinical samples for purposes of public health safety.

A perturbation method for evaluating background subtraction algorithms - Chalidabhongse,T.H.; Kim,K.; Harwood,D.; Davis, Larry S. (Joint IEEE International Workshop on Visual Surveillance and Performance Evaluation of Tracking and Surveillance (VS-PETS), 2003)
We introduce a performance evaluation methodology calledPerturbation Detection Rate (PDR) analysis, for measuring performance of background subtraction (BGS) algorithms. It has some advantages over the commonly used Receiver Operation Characteristics (ROC) analysis. Specifically, it does not require foreground targets or knowledge of fore- ground distributions. It measures the sensitivity of a BGS algorithm in detecting low contrast targets against back- ground as a function of contrast, also depending on how well the model captures mixed (moving) background events. We compare four algorithms having similarities and differ- ences. Three are in [2, 3, 5] while the fourth is recently de- veloped, called Codebook BGS. The latter algorithm quan- tizes sample background values at each pixel into code- books which represent a compressed form of background model for a long image sequence.

Phylogenetic analysis reveals five independent transfers of the chloroplast gene ıt rbcL to the mitochondrial genome in angiosperms - Cummings, Michael P.; Nugent,J. M; Olmstead,R. G; Palmer,J. D (Curr Genet, 2003)
We used the chloroplast gene rbcL as a model to study the frequency and relative timing of transfer of chloroplast sequences to the mitochondrial genome. Southern blot survey of 20 mitochondrial DNAs confirmed three previously reported groups of plants containing rbcL in their mitochondrion, while PCR studies identified a new mitochondrial rbcL. Published and newly determined mitochondrial and chloroplast rbcL sequences were used to reconstruct rbcL phylogeny. The results imply five or six separate interorganellar transfers of rbcL among the angiosperms examined, and hundreds of successful transfers across all flowering plants. By taxonomic criteria, the crucifer transfer is the most ancient, two separate transfers within the grass family are of intermediate ancestry, and the morning-glory transfer is most recent. All five mitochondrial copies of rbcL examined exhibit insertion and/or deletion events that disrupt the reading frame (three are grossly truncated); and all are elevated in the proportion of nonsynonymous substitutions, providing clear evidence that these sequences are pseudogenes.

Predictability of Vibrio Cholerae in Chesapeake Bay - Louis,Valérie R.; Russek-Cohen,Estelle; Choopun,Nipa; Rivera,Irma N. G.; Gangle,Brian; Jiang,Sunny C.; Rubin,Andrea; Patz,Jonathan A.; Huq,Anwar; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2003)
Vibrio cholerae is autochthonous to natural waters and can pose a health risk when it is consumed via untreated water or contaminated shellfish. The correlation between the occurrence of V. cholerae in Chesapeake Bay and environmental factors was investigated over a 3-year period. Water and plankton samples were collected monthly from five shore sampling sites in northern Chesapeake Bay (January 1998 to February 2000) and from research cruise stations on a north-south transect (summers of 1999 and 2000). Enrichment was used to detect culturable V. cholerae, and 21.1% (n = 427) of the samples were positive. As determined by serology tests, the isolates, did not belong to serogroup O1 or O139 associated with cholera epidemics. A direct fluorescent-antibody assay was used to detect V. cholerae O1, and 23.8% (n = 412) of the samples were positive. V. cholerae was more frequently detected during the warmer months and in northern Chesapeake Bay, where the salinity is lower. Statistical models successfully predicted the presence of V. cholerae as a function of water temperature and salinity. Temperatures above 19°C and salinities between 2 and 14 ppt yielded at least a fourfold increase in the number of detectable V. cholerae. The results suggest that salinity variation in Chesapeake Bay or other parameters associated with Susquehanna River inflow contribute to the variability in the occurrence of V. cholerae and that salinity is a useful indicator. Under scenarios of global climate change, increased climate variability, accompanied by higher stream flow rates and warmer temperatures, could favor conditions that increase the occurrence of V. cholerae in Chesapeake Bay.

Probabilistic recognition of human faces from video - Zhou,Shaohua; Krueger,Volker; Chellapa, Rama (Computer Vision and Image Understanding, 2003)
Recognition of human faces using a gallery of still or video images and a probe set of videos is systematically investigated using a probabilistic framework. In still-to-video recognition, where the gallery consists of still images, a time series state space model is proposed to fuse temporal information in a probe video, which simultaneously characterizes the kinematics and identity using a motion vector and an identity variable, respectively. The joint posterior distribution of the motion vector and the identity variable is estimated at each time instant and then propagated to the next time instant. Marginalization over the motion vector yields a robust estimate of the posterior distribution of the identity variable. A computationally efficient sequential importance sampling (SIS) algorithm is developed to estimate the posterior distribution. Empirical results demonstrate that, due to the propagation of the identity variable over time, a degeneracy in posterior probability of the identity variable is achieved to give improved recognition. The gallery is generalized to videos in order to realize video-to-video recognition. An exemplar-based learning strategy is adopted to automatically select video representatives from the gallery, serving as mixture centers in an updated likelihood measure. The SIS algorithm is applied to approximate the posterior distribution of the motion vector, the identity variable, and the exemplar index, whose marginal distribution of the identity variable produces the recognition result. The model formulation is very general and it allows a variety of image representations and transformations. Experimental results using images/videos collected at UMD, NIST/USF, and CMU with pose/illumination variations illustrate the effectiveness of this approach for both still-to-video and video-to-video scenarios with appropriate model choices.
Keywords: Exemplar-based learning; face recognition; sequential importance sampling; Still-to-video; Time series state space model; Video-to-video

A process-algebraic language for probabilistic I/O automata - Stark,E. W; Cleaveland, Rance; Smolka,S. A (CONCUR 2003-Concurrency Theory, 2003)

Random MAX SAT, random MAX CUT, and their phase transitions - Coppersmith,D.; Gamarnik,D.; Hajiaghayi, Mohammad T.; Sorkin,G. B (Proceedings of the fourteenth annual ACM-SIAM symposium on Discrete algorithms, 2003)

Rank constrained recognition under unknown illuminations - Zhou, S.; Chellapa, Rama (Analysis and Modeling of Faces and Gestures, 2003. AMFG 2003. IEEE International Workshop on, 2003)
Recognition under illumination variations is a challenging problem. The key is to successfully separate the illumination source from the observed appearance. Once separated, what remains is invariant to illuminant and appropriate for recognition. Most current efforts employ a Lambertian reflectance model with varying albedo field ignoring both attached and cast shadows, but restrict themselves by using object-specific samples, which undesirably deprives them of recognizing new objects not in the training samples. Using rank constraints on the albedo and the surface normal, we accomplish illumination separation in a more general setting, e.g., with class-specific samples via a factorization approach. In addition, we handle shadows (both attached and cast ones) by treating them as missing values, and resolve the ambiguities in the factorization method by enforcing integrability. As far as recognition is concerned, a bootstrap set which is just a collection of two-dimensional image observations can be utilized to avoid the explicit requirement that three-dimensional information be available. Our approaches produce good recognition results as shown in our experiments using the PIE database.
Keywords: albedo; approach; constrained; database; databases; decomposition; factorization; field; illumination; image; information; Lambertian; lighting; model; object; object-specific; PIE; rank; recognition; reflectance; samples; singular; three-dimensional; two-dimensional; value; variations; visual

Recovery of a Digital Image Collection Through the SDSC/UMD/NARA Prototype Persistent Archive - Smorul,Mike; JaJa, Joseph F.; McCall,Fritz; Brown,Susan Fitch; Moore,Reagan; Marciano,Richard; Chen,Sheau-Yen; Lopez,Rick; Chadduck,Robert (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2003)
The San Diego Supercomputer Center (SDSC), the University of Maryland, and theNational Archives and Records Administration (NARA) are collaborating on building a pilot persistent archive using and extending data grid and digital library technologies. The current prototype consists of node servers at SDSC, University of Maryland, and NARA, connected through the Storage Request Broker (SRB) data grid middleware, and currently holds several terabytes of NARA selected collections. In particular, a historically important image collection that was on the verge of becoming inaccessible was fully restored and ingested into our pilot system. In this report, we describe the methodology behind our approach to fully restore this image collection and the process used to ingest it into the prototype persistent archive. (UMIACS-TR-2003-105)
Keywords: Technical Report

Reduction of Cholera in Bangladeshi Villages by Simple Filtration - Rita R Colwell; Huq,Anwar; M. Sirajul Islam; K. M. A. Aziz; Yunus,M.; N. Huda Khan; A. Mahmud; Sack,R. Bradley; Nair,G. B.; J. Chakraborty; Sack,David A.; E. Russek-Cohen (Proceedings of the National Academy of SciencesPNAS, 2003)
Based on results of ecological studies demonstrating that Vibrio cholerae, the etiological agent of epidemic cholera, is commensal to zooplankton, notably copepods, a simple filtration procedure was developed whereby zooplankton, most phytoplankton, and particulates >20 μm were removed from water before use. Effective deployment of this filtration procedure, from September 1999 through July 2002 in 65 villages of rural Bangladesh, of which the total population for the entire study comprised ≈133,000 individuals, yielded a 48% reduction in cholera (P < 0.005) compared with the control.

Replicated studies: building a body of knowledge about software reading techniques - Shull, F.; Carver, J.; Travassos,G.H.; Maldonado,J.C.; Conradi,R.; Basili, Victor R. (SERIES ON SOFTWARE ENGINEERING AND KNOWLEDGE ENGINEERING, 2003)

Robust Face Recognition in the Presence of Clutter - Rajagopalan, AN; Chellapa, Rama; Koterba,Nathan (Audio- and Video-Based Biometric Person AuthenticationAudio- and Video-Based Biometric Person Authentication, 2003)
We propose a new method within the framework of principal component analysis to robustly recognize faces in the presence of clutter. The traditional eigenface recognition method performs poorly when confronted with the more general task of recognizing faces appearing against a background. It misses faces completely or throws up many false alarms. We argue in favor of learning the distribution of background patterns and show how this can be done for a given test image. An eigenbackground space is constructed and this space in conjunction with the eigenface space is used to impart robustness in the presence of background. A suitable classifier is derived to distinguish non-face patterns from faces. When tested on real images, the performance of the proposed method is found to be quite good.

A search engine for 3D models - Funkhouser,Thomas; Min,Patrick; Kazhdan,Michael; Chen,Joyce; Halderman,Alex; Dobkin,David; Jacobs, David W. (ACM Trans. Graph., 2003)
As the number of 3D models available on the Web grows, there is an increasing need for a search engine to help people find them. Unfortunately, traditional text-based search techniques are not always effective for 3D data. In this article, we investigate new shape-based search methods. The key challenges are to develop query methods simple enough for novice users and matching algorithms robust enough to work for arbitrary polygonal models. We present a Web-based search engine system that supports queries based on 3D sketches, 2D sketches, 3D models, and/or text keywords. For the shape-based queries, we have developed a new matching algorithm that uses spherical harmonics to compute discriminating similarity measures without requiring repair of model degeneracies or alignment of orientations. It provides 46 to 245% better performance than related shape-matching methods during precision--recall experiments, and it is fast enough to return query results from a repository of 20,000 models in under a second. The net result is a growing interactive index of 3D models available on the Web (i.e., a Google for 3D models).
Keywords: Search engine; shape matching; shape representation; shape retrieval

Seven days in the life of a robotic agent - Chong,W.; O'Donovan-Anderson,M.; Okamoto,Y.; Perlis, Don (Innovative Concepts for Agent-Based Systems, 2003)

Shape and motion driven particle filtering for human body tracking - Yamamoto, T.; Chellapa, Rama (Multimedia and Expo, 2003. ICME '03. Proceedings. 2003 International Conference on, 2003)
In this paper, we propose a method to recover 3D human body motion from a video acquired by a single static camera. In order to estimate the complex state distribution of a human body, we adopt the particle filtering framework. We present the human body using several layers of representation and compose the whole body step by step. In this way, more effective particles are generated and ineffective particles are removed as we process each layer. In order to deal with the rotational motion, the frequency of rotation is obtained using a preprocessing operation. In the preprocessing step, the variance of the motion field at each image is computed, and the frequency of rotation is estimated. The estimated frequency is used for the state update in the algorithm. We successfully track the movement of figure skaters in TV broadcast image sequence, and recover the 3D shape and motion of the skater.
Keywords: 3D; body; broadcast; camera; cameras; estimation; Filtering; framework; human; image; MOTION; motion; particle; processing; rotational; sequence; sequences; signal; single; static; theory; tracking; TV; video

Simultaneous tracking and recognition of human faces from video - Zhou,Shaohua; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2003. Proceedings. (ICASSP '03). 2003 IEEE International Conference on, 2003)
The paper investigates the interaction between tracking and recognition of human faces from video under a framework proposed earlier (Shaohua Zhou et al., Proc. 5th Int. Conf. on Face and Gesture Recog., 2002; Shaohua Zhou and Chellappa, R., Proc. European Conf. on Computer Vision, 2002), where a time series model is used to resolve the uncertainties in both tracking and recognition. However, our earlier efforts employed only a simple likelihood measurement in the form of a Laplacian density to deal with appearance changes between frames and between the observation and gallery images, yielding poor accuracies in both tracking and recognition when confronted by pose and illumination variations. The interaction between tracking and recognition was not well understood. We address the interdependence between tracking and recognition using a series of experiments and quantify the interacting nature of tracking and recognition.
Keywords: appearance; changes; density; Face; human; illumination; Laplacian; model; optical; pose; processing; recognition; series; series; signal; TIME; tracking; variations; video; video

Starting an intergenerational technology design team: a case study - Knudtzon,Kendra; Druin, Allison; Kaplan,Nancy; Summers,Kathryn; Chisik,Yoram; Kulkarni,Rahul; Moulthrop,Stuart; Weeks,Holly; Bederson, Benjamin B. (Proceedings of the 2003 conference on Interaction design and children, 2003)
This paper presents a case study of the first three months of a new intergenerational design team with children ages 10--13. It discusses the research and design methods used for working with children of this age group, the challenges and opportunities of starting a new team, and the lessons learned.
Keywords: children; cooperative inquiry; design methods; educational applications; intergenerational design teams; participatory design

Statistical bias and the accuracy of 3d reconstruction from video - Chowdhury, A.R.; Chellapa, Rama (in International Journal of Computer Vision, 2003)
The present state of the art in determining the error statistics in3D reconstruction from video concentrates on estimating the error covariance. A different source of error which has not received much attention in the computer vision community, but has been noted by psychophysicists, is the fact "that it is hard to explain ... the existence of systematic biases in observers' magnitude estimation of perceived depth" (Todd, 1998). In this paper, we prove that the depth estimate is statistically biased, derive a precise expression for it, and hypothesize that our analysis can be a possible explanation for the experimental observations. Many structure from motion (SfM) algorithms that reconstruct a scene from a video sequence pose the problem in a linear least squares framework Ax = b. It is a well- known fact that the least squares estimate is biased if the system matrix A is noisy. In SfM, the matrix A contains the image coordinates, which are always difficult to obtain precisely; thus it is expected that the structure and motion estimates in such a formulation of the problem would be biased. Though previous authors have analyzed the bias in 3D motion estimation from stereo, to the best of our knowledge, the statistical bias in 3D reconstruction from video has not been studied in the vision community. We show that even with a perfect motion estimate, the depth estimate is statistically biased. Existing results on the minimum achievable variance of the estimator are extended by deriving a generalized Cramer-Rao lower bound. Through simulations, we demonstrate the effects of camera motion parameters on the bias and give numerical examples to highlight the importance of compensating for it.

Statistical Error Propagation in 3D Modeling From Monocular Video - RoyChowdhury,Amit; Chellapa, Rama (Computer Vision and Pattern Recognition Workshop, 2003. CVPRW '03. Conference on, 2003)
A significant portion of recent research in computer vision has focused on issues related to sensitivity and robustness of existing techniques. In this paper, we study the classical structure from motion problem and analyze how the statistics representing the quality of the input video propagates through the reconstruction algorithm and affects the quality of the output reconstruction. Specifically, we show that it is possible to derive analytical expressions of the first and second order statistics (bias and error covariance) of the solution as a function of the statistics of the input. We concentrate on the case of reconstruction from a monocular video, where the small baseline makes any algorithm very susceptible to noise in the motion estimates from the video sequence. We derive an expression relating the error covariance of the reconstruction to the error covariance of the feature tracks in the input video. This is done using the implicit function theorem of real analysis and does not require strong statistical assumptions. Next, we prove that the 3D reconstruction is statistically biased, derive an expression for it and show that it is numerically significant. Combining these two results, we also establish a new bound on the minimum error in the depth reconstruction. We present the numerical significance of these analytical results on real video data.

Statistical physical model for foliage clutter in ultra-wideband synthetic aperture radar images - Banerjee,Amit; Chellapa, Rama (Journal of the Optical Society of America AThe Journal of the Optical Society of America A, 2003)
Analyzing foliage-penetrating (FOPEN) ultra-wideband synthetic aperture radar (SAR) images is a challenging problem owing to the noisy and impulsive nature of foliage clutter. Indeed, many target-detection algorithms for FOPEN SAR data are characterized by high false-alarm rates. In this work, a statistical–physical model for foliage clutter is proposed that explains the presence of outliers in the data and suggests the use of symmetric alpha-stable (SαS) distributions for accurate clutter modeling. Furthermore, with the use of general assumptions of the noise sources and propagation conditions, the proposed model relates the parameters of the SαS model to physical parameters such as the attenuation coefficient and foliage density.
Keywords: IMAGE PROCESSING; Remote sensing and sensors

Statistical shape theory for activity modeling - Vaswani, N.; Chowdhury, A.R.; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2003. Proceedings. (ICASSP '03). 2003 IEEE International Conference on, 2003)
Monitoring activities in a certain region from video data is an important surveillance problem. The goal is to learn the pattern of normal activities and detect unusual ones by identifying activities that deviate appreciably from the typical ones. We propose an approach using statistical shape theory based on the shape model of D.G. Kendall et al. (see "Shape and Shape Theory", John Wiley and Sons, 1999). In a low resolution video, each moving object is best represented as a moving point mass or particle. In this case, an activity can be defined by the interactions of all or some of these moving particles over time. We model this configuration of the particles by a polygonal shape formed from the locations of the points in a frame and the activity by the deformation of the polygons in time. These parameters are learned for each typical activity. Given a test video sequence, an activity is classified as abnormal if the probability for the sequence (represented by the mean shape and the dynamics of the deviations), given the model, is below a certain threshold The approach gives very encouraging results in surveillance applications using a single camera and is able to identify various kinds of abnormal behavior.
Keywords: abnormal; activities; activity; analysis; behavior; classification; data; image; mass; matching; modeling; monitoring; moving; normal; particle; pattern; pattern; point; polygonal; probability; problem; processing; sequence; sequences; SHAPE; shape; signal; statistical; Surveillance; surveillance; theory; video

Stochastic Approximation and Rate-Distortion Analysis for Robust Structure and Motion Estimation - Chowdhury,Amit K. Roy; Chellapa, Rama (International Journal of Computer Vision, 2003)
Recent research on structure and motion recovery has focused on issues related to sensitivity and robustness of existing techniques. One possible reason is that in practical applications, the underlying assumptions made by existing algorithms are often violated. In this paper, we propose a framework for 3D reconstruction from short monocular video sequences taking into account the statistical errors in reconstruction algorithms. Detailed error analysis is especially important for this problem because the motion between pairs of frames is small and slight perturbations in its estimates can lead to large errors in 3D reconstruction. We focus on the following issues: physical sources of errors, their experimental and theoretical analysis, robust estimation techniques and measures for characterizing the quality of the final reconstruction. We derive a precise relationship between the error in the reconstruction and the error in the image correspondences. The error analysis is used to design a robust, recursive multi-frame fusion algorithm using “stochastic approximation” as the framework since it is capable of dealing with incomplete information about errors in observations. Rate-distortion analysis is proposed for evaluating the quality of the final reconstruction as a function of the number of frames and the error in the image correspondences. Finally, to demonstrate the effectiveness of the algorithm, examples of depth reconstruction are shown for different video sequences.

A Survey of Shape Similarity Assessment Algorithms for Product Design and Manufacturing Applications - Cardone, Antonio; Gupta, Satyandra K.; Karnik,Mukul (Journal of Computing and Information Science in EngineeringJ. Comput. Inf. Sci. Eng., 2003)
Keywords: CAD; computational geometry; production engineering computing; spatial reasoning

A system for generating process and material selection advice during embodiment design of mechanical components - Gupta,S.K.; Chen,Y.; Feng,S.; Sriram,R. (Journal of manufacturing systems, 2003)
This paper describes a systematic approach to material and process selection during theembodiment design of mechanical components and a system for generating process and material selection advice. Quite often during the embodiment design stage, design requirements are not precisely defined. Therefore, the system described in this paper accounts for imprecision in design requirements during generation and evaluation of alternative process sequences and material options. To reduce the computational effort, the system uses a depth-first branch-and- bound search algorithm. This aids in exploring promising process sequences and material options that can be used to meet the given set of design requirements. Various process sequences and material options are evaluated by using a commercial cost estimation tool.

Technology probes: inspiring design for and with families - Hutchinson,Hilary; Mackay,Wendy; Westerlund,Bo; Bederson, Benjamin B.; Druin, Allison; Plaisant, Catherine; Beaudouin-Lafon,Michel; Conversy,Stéphane; Evans,Helen; Hansen,Heiko; Roussel,Nicolas; Eiderbäck,Björn (Proceedings of the SIGCHI conference on Human factors in computing systems, 2003)
We describe a new method for use in the process of co-designing technologies with users called technology probes. Technology probes are simple, flexible, adaptable technologies with three interdisciplinary goals: the social science goal of understanding the needs and desires of users in a real-world setting, the engineering goal of field-testing the technology, and the design goal of inspiring users and researchers to think about new technologies. We present the results of designing and deploying two technology probes, the messageProbe and the videoProbe, with diverse families in France, Sweden, and the U.S. We conclude with our plans for creating new technologies for and with families based on our experiences.
Keywords: computer mediated communication; ethnography; Home; participatory design and cooperative design

TelegraphCQ: An architectural status report - Krishnamurthy, S.; Chandrasekaran,S.; Cooper,O.; Deshpande, Amol; Franklin,M.J.; Hellerstein,J. M; Hong,W.; Madden,S.; Reiss,F.; Shah,M. A (IEEE Data Engineering Bulletin, 2003)

TelegraphCQ: continuous dataflow processing - Chandrasekaran,Sirish; Cooper,Owen; Deshpande, Amol; Franklin,Michael J.; Hellerstein,Joseph M.; Wei Hong; Krishnamurthy,Sailesh; Madden,Samuel R.; Reiss,Fred; Shah,Mehul A. (Proceedings of the 2003 ACM SIGMOD international conference on Management of data, 2003)

Towards a view invariant gait recognition algorithm - Kale, A.; Chowdhury, A.K.R.; Chellapa, Rama (Proceedings. IEEE Conference on Advanced Video and Signal Based Surveillance, 2003., 2003)
Human gait is a spatio-temporal phenomenon and typifies the motion characteristics of an individual. The gait of a person is easily recognizable when extracted from a side-view of the person. Accordingly, gait-recognition algorithms work best when presented with images where the person walks parallel to the camera image plane. However, it is not realistic to expect this assumption to be valid in most real-life scenarios. Hence, it is important to develop methods whereby the side-view can be generated from any other arbitrary view in a simple, yet accurate, manner. This is the main theme of the paper. We show that if the person is far enough from the camera, it is possible to synthesize a side view (referred to as canonical view) from any other arbitrary view using a single camera. Two methods are proposed for doing this: (i) using the perspective projection model; (ii) using the optical flow based structure from motion equations. A simple camera calibration scheme for this method is also proposed. Examples of synthesized views are presented. Preliminary testing with gait recognition algorithms gives encouraging results. A by-product of this method is a simple algorithm for synthesizing novel views of a planar scene.
Keywords: (access; algorithm; analysis; Biometrics; biometrics; Calibration; calibration; camera; canonical; control); equations; flow; Gait; gait; human; image; invariant; model; MOTION; optical; perspective; phenomenon; projection; recognition; scheme; sequences; spatio-temporal; view; view

Towards formal but flexible scenarios - Sengupta,B.; Cleaveland, Rance (2nd International Workshop on Scenarios and State Machines: Models, Algorithms and Tools, 2003)

TRIM: A tool for triggered message sequence charts - Sengupta,B.; Cleaveland, Rance (Computer Aided Verification, 2003)

Understanding Computer User Frustration: Measuring and Modeling the Disruption from Poor Designs - Bessiere,Katie; Ceaparu,Irina; Lazar,Jonathan; Robinson,John; Shneiderman, Ben (Technical Reports from UMIACS, 2003)
User frustration in the use of information and computing technology is apervasive and persistent problem. When computers crash, network congestion causes delays, and poor user interfaces trigger confusion there are dramatic consequences for individuals, organizations, and society. These frustrations not only cause personal dissatisfaction and loss of self-efficacy, but may disrupt workplaces, slow learning, and reduce participation in local and national communities. We propose a Computing Frustration Model with incident specific and individual variables to guide research. Our study of 108 computer users shows high levels of frustration and loss of 1/3 to 1/2 of time spent. The importance of the users' goals and the severity of the disruption were correlated with frustration. Those who had strong self-efficacy, indicated by a willingness to stick to solving the problem, reported lower levels of frustration. Implications for users, software developers, managers, and policymakers are discussed. Keywords: user frustration, user interface design, training, helpdesk, computer experience, computer anxiety (UMIACS-TR-2002-89) (HCIL-TR-2002-18)
Keywords: Technical Report

On the use of flow migration for handling short-term overloads - Kuo,Kuo-Tung; Phuvoravan,S.; Bhattacharjee, Bobby; Jun La,R.; Shayman,M.; Chang,Hyeong Soo (Global Telecommunications Conference, 2003. GLOBECOM '03. IEEE, 2003)
In this work, we investigate flow migration as a mechanism to sustain QoS to network users during short-term overloads in the context of an MPLS IP network. We experiment with three different control techniques: static long-term optimal mapping of flows to LSPs; on-line locally optimal mapping of flows to LSPs at flow set-up time; and dynamic flow migration in response to transient congestion. These techniques are applicable over different timescales, have different run-time overheads, and require different levels of monitoring and control software inside the network. We present results both from detailed simulations and a complete implementation using software IP routers. We use voice-over-IP as our test application, and show that if end-to-end quality is to be maintained during short unpredictable bursts of high load, then a fast-timescale control such as migration is required.
Keywords: computing; CONGESTION; congestion; CONTROL; control; dynamic; end-to-end; engineering; fast-timescale; flow; Internet; IP; label; long-term; mapping; migration; MPLS; multiprotocol; network; network; networks; of; optimal; overloads; protocol; QoS; QUALITY; quality; routers; routing; service; set-up; short-term; software; software; static; switching; Telecommunication; telephony; time; transient; voice-over-IP

Using Visualization Tools to Gain Insight Into Your Data - Plaisant, Catherine; Chintalapani,G.; Lukehart,C.; Schiro,D.; Ryan,J. (SPE Annual Technical Conference and Exhibition, 2003)
When the term ‘visualization’ is used in the oil and gas industry, it is usually referring to the viewing of complex geologic structures in three-dimensional space. This paper illustrates insights gained by applying interactive visual environments to petroleum industry data that has traditionally been presented in spreadsheets, line graphs, and bar charts. Two information visualization tools, Treemap and SpaceTree, will be shown applied to a variety of oilfield related data.

Video based rendering of planar dynamic scenes - Kale, A.; Chowdhury, A.K.R.; Chellapa, Rama (Multimedia and Expo, 2003. ICME '03. Proceedings. 2003 International Conference on, 2003)
In this paper, we propose a method to synthesize arbitrary views of a planar scene from a monocular video sequence of it. The 3-D direction of motion of the object is robustly estimated from the video sequence. Given this direction any other view of the object can be synthesized through a perspective projection approach, under assumptions of planarity. If the distance of the object from the camera is large, a planar approximation is reasonable even for non-planar scenes. Such a method has many important applications, one of them being gait recognition where a side view of the person is required. Our method can be used to synthesize the side-view of the person in case he/she does not present a side view to the camera. Since the planarity assumption is often an approximation, the effects of non-planarity can lead to inaccuracies in rendering and needs to be corrected for. Regions where this happens are examined and a simple technique based on weak perspective approximation is proposed to offset rendering inaccuracies. Examples of synthesized views using our method and performance evaluation are presented.
Keywords: (computer; 3D; analysis; approximation; based; camera; cameras; direction; dynamic; graphics); image; monocular; MOTION; perspective; planar; processing; rendering; rendering; scenes; sequence; sequences; signal; video; weak

Video synthesis of arbitrary views for approximately planar scenes - Chowdhury, A.K.R.; Kale, A.; Chellapa, Rama (Acoustics, Speech, and Signal Processing, 2003. Proceedings. (ICASSP '03). 2003 IEEE International Conference on, 2003)
In this paper, we propose a method to synthesize arbitrary views of a planar scene, given a monocular video sequence. The method is based on the availability of knowledge of the angle between the original and synthesized views. Such a method has many important applications, one of them being gait recognition. Gait recognition algorithms rely on the availability of an approximate side-view of the person. From a realistic viewpoint, such an assumption is impractical in surveillance applications and it is of interest to develop methods to synthesize a side view of the person, given an arbitrary view. For large distances from the camera, a planar approximation for the individual can be assumed. In this paper, we propose a perspective projection approach for recovering the direction of motion of the person purely from the video data, followed by synthesis of a new video sequence at a different angle. The algorithm works purely in the image and video domain, though 3D structure plays an implicit role in its theoretical justification. Examples of synthesized views using our method and performance evaluation are presented.
Keywords: (access; 3D; applications; approach; approximately; approximation; arbitrary; Biometrics; control); data; direction; estimation; evaluation; Gait; image; monocular; MOTION; performance; perspective; planar; processing; projection; recognition; recovery; scenes; sequence; sequences; side; signal; structure; Surveillance; surveillance; synthesis; synthesized; video; view; views

VIDEO SYNTHESIS OF ARBITRARY VIEWS FOR APPROXIMATELY PLANAR SCENES - Chowdhury, A.R.; Kale, A.; Chellapa, Rama (IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS SPEECH AND SIGNAL PROCESSING, 2003)

View synthesis of articulating humans using visual hull - Yue,Zhanfeng; Liang Zhao; Chellapa, Rama (Multimedia and Expo, 2003. ICME '03. Proceedings. 2003 International Conference on, 2003)
In this paper, we present a method, which combines image-based visual hull and human body part segmentation for overcoming the inability of the visual hull method to reconstruct concave regions. The virtual silhouette image corresponding to the given viewing direction is first produced with image-based visual hull. Human body part localization technique is used to segment the input images and the rendered virtual silhouette image into convex body parts. The body parts in the virtual view are generated separately from the corresponding body parts in the input views and then assembled together. The previously rendered silhouette image is used to locate the corresponding body parts in input views and avoid the unconnected or squeezed regions in the assembled final view. Experiments show that this method can improve the reconstruction of concave regions for human postures and texture mapping.
Keywords: analysis; body; convex; gesture; hull; human; image; image-based; image; mapping; MOTION; part; parts; postures; recognition; reconstruction; segmentation; silhouette; synthesis; TEXTURE; texture; view; virtual; visual

The virtual microscope - Catalyurek,U.; Beynon,M. D; Chang,Chialin; Kurc, T.; Sussman, Alan; Saltz, J. (IEEE Transactions on Information Technology in Biomedicine, 2003)
We present the design and implementation of the virtual microscope, a software system employing a client/server architecture to provide a realistic emulation of a high power light microscope. The system provides a form of completely digital telepathology, allowing simultaneous access to archived digital slide images by multiple clients. The main problem the system targets is storing and processing the extremely large quantities of data required to represent a collection of slides. The virtual microscope client software runs on the end user's PC or workstation, while database software for storing, retrieving and processing the microscope image data runs on a parallel computer or on a set of workstations at one or more potentially remote sites. We have designed and implemented two versions of the data server software. One implementation is a customization of a database system framework that is optimized for a tightly coupled parallel machine with attached local disks. The second implementation is component-based, and has been designed to accommodate access to and processing of data in a distributed, heterogeneous environment. We also have developed caching client software, implemented in Java, to achieve good response time and portability across different computer platforms. The performance results presented show that the Virtual Microscope systems scales well, so that many clients can be adequately serviced by an appropriately configured data server.
Keywords: biomedical optical imaging; client software; client/server architecture; Computer architecture; Computer Graphics; computer platforms; Computer simulation; Concurrent computing; configured data server; data server software; database management systems; database software; Database systems; digital slide images; digital telepathology; diseases; emulation; Environment; Equipment Design; Equipment Failure Analysis; high power light microscope; Image databases; Image Enhancement; Image Interpretation, Computer-Assisted; Image retrieval; Information retrieval; Information Storage and Retrieval; java; local disks; microscope image data; Microscopy; multiple clients; optical microscopy; PACS; software; Software design; software system; Software systems; Systems Integration; Telepathology; User-Computer Interface; virtual microscope design; Virtual reality; Workstations

The World's Information in Digital Libraries - Plaisant, Catherine; Marchimini,G.; Bruns,T.; Komlodi,A.; Campbell,L.; Rose,A.; Ding,G.M.; Beale Jr,J.; Nolet,V.; Shneiderman, Ben; others (The craft of information visualization: readings and reflectionsThe craft of information visualization: readings and reflections, 2003)

3D face reconstruction from video using a generic model - Chowdhury, A.R.; Chellapa, Rama; Krishnamurthy, S.; Vo, T. (Multimedia and Expo, 2002. ICME '02. Proceedings. 2002 IEEE International Conference on, 2002)
Reconstructing a 3D model of a human face from a video sequence is an important problem in computer vision, with applications to recognition, surveillance, multimedia etc. However, the quality of 3D reconstructions using structure from motion (SfM) algorithms is often not satisfactory. One common method of overcoming this problem is to use a generic model of a face. Existing work using this approach initializes the reconstruction algorithm with this generic model. The problem with this approach is that the algorithm can converge to a solution very close to this initial value, resulting in a reconstruction which resembles the generic model rather than the particular face in the video which needs to be modeled. We propose a method of 3D reconstruction of a human face from video in which the 3D reconstruction algorithm and the generic model are handled separately. A 3D estimate is obtained purely from the video sequence using SfM algorithms without use of the generic model. The final 3D model is obtained after combining the SfM estimate and the generic model using an energy function that corrects for the errors in the estimate by comparing local regions in the two models. The optimization is done using a Markov chain Monte Carlo (MCMC) sampling strategy. The main advantage of our algorithm over others is that it is able to retain the specific features of the face in the video sequence even when these features are different from those of the generic model. The evolution of the 3D model through the various stages of the algorithm is presented.
Keywords: 3D; algorithm; algorithms; analysis; Carlo; chain; Computer; Face; from; function; generic; human; image; Markov; MCMC; methods; model; Monte; MOTION; optimisation; OPTIMIZATION; processes; processing; recognition; reconstruction; reconstruction; sampling; sequence; sequences; SfM; signal; structure; surveillance; video; vision

Active Harmony: Towards Automated Performance Tuning - Tapus, C.; I-Hsin Chung; Hollingsworth, Jeffrey K (Supercomputing, ACM/IEEE 2002 Conference, 2002)
In this paper, we present the Active Harmony automated runtime tuning system. We describe the interface used by programs to make applications tunable. We present the Library Specification Layer which helps program library developers expose multiple variations of the same API using different algorithms.The Library Specification Language helps to select the most appropriate program library to tune the overall performance. We also present the optimization algorithm used to adjust parameters in the application and the libraries. Finally, we present results that show how the system is able to tune several real applications. The automated tuning system is able to tune the application parameers to within a few percent of the best value after evaluating only 11 out of over 1,700 possible configurations.
Keywords: Application software; Automatic control; Computational modeling; Computer science; Computerized monitoring; Control systems; grid computing; Runtime library; software libraries; Specification languages

An adaptive framework for tunable consistency and timeliness using replication - Krishnamurthy, S.; Sanders,W. H.; Michel Cukier (2002)
One well-known challenge in using replication to service multiple clients concurrently is that of delivering a timely and consistent response to the clients. In this paper, we address this problem in the context of client applications that have specific temporal and consistency requirements. These applications can tolerate a certain degree of relaxed consistency, in exchange for better response time. We propose a flexible QoS model that allows these clients to specify their temporal and consistency constraints. In order to select replicas to serve these clients, we need to control of the inconsistency of the replicas, so that we have a large enough pool of replicas with the appropriate state to meet a client's timeliness, consistency, and dependability requirements. We describe an adaptive framework that uses lazy update propagation to control the replica inconsistency and employs a probabilistic approach to select replicas dynamically to service a client, based on its QoS specification. The probabilistic approach predicts the ability of a replica to meet a client's QoS specification by using the performance history collected by monitoring the replicas at runtime. We conclude with experimental results based on our implementation.
Keywords: adaptive framework; concurrent multiple client service; consistency requirements; dependability requirements; distributed object management; flexible QoS model; lazy update propagation; performance history; probabilistic approach; Protocols; quality of service; replication; temporal requirements; timely consistent response; tunable consistency; tunable timeliness

Analysis of 16S-23S rRNA intergenic spacer of Vibrio cholerae and Vibrio mimicus for detection of these species - Chun,J.; Rivera,I. N. G.; Rita R Colwell (METHODS IN MOLECULAR BIOLOGY, 2002)

Analysis of stage-specific gene expression in the bloodstream and the procyclic form of Trypanosoma brucei using a genomic DNA-microarray - Diehl,Susanne; Diehl,Frank; El‐Sayed, Najib M.; Clayton,Christine; Hoheisel,Jörg D. (Molecular and Biochemical Parasitology, 2002)
A microarray comprising 21[punctuation space]024 different PCR products spotted on glass slides was constructed for gene expression studies on Trypanosoma brucei. The arrayed fragments were generated from a T. brucei shotgun clone library, which had been prepared from randomly sheared and size-fractionated genomic DNA. For the identification of stage-specific gene activity, total RNA from in vitro cultures of the human, long slender form and the insect, procyclic form of the parasite was labelled and hybridised to the microarray. Approximately 75% of the genomic fragments produced a signal and about 2% exhibited significant differences between the transcript levels in the bloodstream and procyclic forms. A few results were confirmed by Northern blot analysis or reverse-transcription and PCR. Three hundred differentially regulated clones have been selected for sequencing. So far, of 33 clones that showed about 2-fold or more over-expression in bloodstream forms, 15 contained sequences similar to those of VSG expression sites and at least six others appeared non-protein-coding. Of 29 procyclic-specific clones, at least eight appeared not to be protein-coding. A surprisingly large proportion of known regulated genes was already identified in this small sample, and some new ones were found, illustrating the utility of genomic arrays.
Keywords: Expression; Gene; Microarray; Regulation; Trypanosoma brucei

An Augmented Visual Query Mechanism for Finding Patterns in Time Series Data - Keogh,Eamonn; Hochheiser,Harry; Shneiderman, Ben (Flexible Query Answering SystemsFlexible Query Answering Systems, 2002)
Relatively few query tools exist for data exploration and pattern identification in time series data sets. In previous work we introduced Timeboxes . Timeboxes are rectangular, direct-manipulation queries for studying time-series datasets. We demonstrated how Timeboxes can be used to support interactive exploration via dynamic queries, along with overviews of query results and drag-and-drop support for query-by-example. In this paper, we extend our work by introducing Variable Time Timeboxes (VTT). VTTs are a natural generalization of Timeboxes, which permit the specification of queries that allow a degree of uncertainty in the time axis. We carefully motivate the need for these more expressive queries, and demonstrate the utility of our approach on several data sets.

A Bayesian Approach to Simultaneous Motion Estimation of Multiple Independently Moving Objects - Qian, G.; Chellapa, Rama; Zheng,Q. (INTERNATIONAL CONFERENCE ON PATTERN RECOGNITION, 2002)
In this paper, the problem of simultaneous motion estima-tion of multiple independently moving objects is addressed. A novel Bayesian approach is designed for solving this prob- lem using the sequential importance sampling (SIS) method. In the proposed algorithm, a balancing step is added into the SIS procedure to preserve samples of low weights so that all objects have enough samples to propagate empirical motion distributions. By using the proposed algorithm, the relative motions of all moving objects with respect to camera can be simultaneously estimated . This algorithm has been tested on both synthetic and real image sequences. Improved re- sults have been achieved.

Bayesian methods for face recognition from video - Chellapa, Rama; Zhou,Shaohua; Li,Baoxin (Acoustics, Speech, and Signal Processing (ICASSP), 2002 IEEE International Conference on, 2002)
Face recognition (FR) from video necessitates simultaneously solving two asks, recognition and tracking. To accommodate the video, a time series state space model is introduced in a Bayesian approach. Given this model, the goal reduces to estimating the posterior distribution of the state vector given the observations up to the present. The Sequential Importance Sampling (SIS) technique is invoked to generate a numerical solution to this model. However, the ultimate goal is to estimate the posterior distribution of the identity of humans for recognition purposes. Presented here are two methods to approximate the above distribution under different experimental scenarios.

Bayesian structure from motion using inertial information - Qian,Gang; Chellapa, Rama; Qinfen Zheng (Image Processing. 2002. Proceedings. 2002 International Conference on, 2002)
A novel approach to Bayesian structure from motion (SfM) using inertial information and sequential importance sampling (SIS) is presented. The inertial information is obtained from camera-mounted inertial sensors and is used in the Bayesian SfM approach as prior knowledge of the camera motion in the sampling algorithm. Experimental results using both synthetic and real images show that, when inertial information is used, more accurate results can be obtained or the same estimation accuracy can be obtained at a lower cost.
Keywords: 3D; analysis; Bayes; Bayesian; camera; estimation; image; images; importance; inertial; information; methods; MOTION; motion; parameter; processing; real; reconstruction; sampling; scene; sensors; sequence; sequences; sequential; signal; structure-from-motion; synthetic; systems; video

Characterization of Pseudoalteromonas citrea and P. nigrifaciens Isolated from Different Ecological Habitats Based on REP-PCR Genomic Fingerprints - Ivanova,Elena P.; Matte,Glavur R.; Matte,Maria H.; Coenye,Tom; Huq,Anwarul; Rita R Colwell (Systematic and Applied Microbiology, 2002)
SummaryDNA primers corresponding to conserved repetitive interspersed genomic motifs and PCR were used to show that REP, ERIC and BOX-like DNA sequences are present in marine, oxidative, Gram-negative Pseudoalteromonas strains. REP, ERIC and BOX-PCR were used for rapid molecular characterization of both the type species of the genus and environmental strains isolated from samples collected in different geographical areas. PCR-generated genomic fingerprint patterns were found to be both complex and strain specific. Analysis of the genotypic structure of phenotypically diverse P. citrea revealed a geographic clustering of Far Eastern brown-pigmented, agar-digesting strains of this species. Marine isolates of P. nigrifaciens with 67–70% DNA relatedness generated genomic patterns different from those of the type strain and formed a separate cluster. It is concluded that REP, ERIC and BOX-PCR are effective in generating strain specific patterns that can be used to elucidate geographic distribution, with these genomic patterns providing a valuable biogeographic criterion.
Keywords: biogeography; BOX-PCR; ERIC; Pseudoalteromonas; REP

CHI@20: fighting our way from marginality to power - Shneiderman, Ben; Card,Stuart; Norman,Donald A.; Tremaine,Marilyn; Waldrop,M. Mitchell (CHI '02 extended abstracts on Human factors in computing systems, 2002)
The Special Interest Group on Computer Human Interaction (SIGCHI) has had a successful history of 20 years of growth in its numbers and influence. To help guide the continued evolution of the academic discipline and professional community, we invite several senior members to offer their visions for what the field of CHI actually accomplished over the past several decades, and what do we still need to accomplish? What do we need to do differently/ better/smarter? What haven't we tried because the technology, the money or the will wasn't there in the past, but perhaps is now.The CHI field is more than just technology. We understand that our work can have a profound effect on individuals, families, neighborhoods, corporations, and countries. We know that we can influence education, commerce, healthcare, and government. How can we contribute to bridging the digital divides in developed and developing countries? What agendas can we offer for the academic, research, industrial, and civic spheres for the next 20 years? How can we be more ambitious? How can we truly serve human needs.
Keywords: education; future vision; Human-computer interaction; practice; professional; THEORY; usability engineering

Combinatorial Algorithms for Design of DNA Arrays - Hannenhalli, Sridhar; Hubbell,Earl; Lipshutz,Robert; Pevzner,Pavel (Chip TechnologyChip Technology, 2002)
Optimal design of DNA arrays requires the development of algorithms with two-fold goals: reducing the effects caused by unintended illumination ( border length minimization problem ) and reducing the complexity of masks ( mask decomposition problem ). We describe algorithms that reduce the number of rectangles in mask decomposition by 20–30% as compared to a standard array design under the assumption that the arrangement of oligonucleotides on the array is fixed. This algorithm produces provably optimal solution for all studied real instances of array design. We also address the difficult problem of finding an arrangement which minimizes the border length and come up with a new idea of threading that significantly reduces the border length as compared to standard designs.

A Comparison of Unified Modelling Language (UML) and Specification and Description Language (SDL) - Marshini Chetty (2002)
This report serves as a basic introduction to the formal specification languages UML and SDL. It also includes a comparison of the two languages.
Keywords: D.2 SOFTWARE ENGINEERING

On the Complexity of Plan Adaptation by Derivational Analogy in a Universal Classical Planning Framework - Au,Tsz-Chiu; Muñoz-Avila,Héctor; Nau, Dana S. (Advances in Case-Based Reasoning, 2002)
In this paper we present an algorithm called DerUCP, which can be regarded as a general model for plan adaptation using Derivational Analogy. Using DerUCP, we show that previous results on the complexity of plan adaptation do not apply to Derivational Analogy. We also show that Derivational Analogy can potentially produce exponential reductions in the size of the search space generated by a planning system.
Keywords: Computer science

A configurable CORBA gateway for providing adaptable system properties - Seri,M.; Courtney,T.; Michel Cukier; Gupta,V.; Krishnmamurthy,S.; Lyons,J.; Ramasamy,H.; Ren,J.; Sanders,W. H. (2002)

COTS-based software development: Processes and open issues - Morisio,M; Seaman,C.B; Basili, Victor R.; Parra,A.T; Kraft,S.E; Condon,S.E (Journal of Systems and Software, 2002)
The work described in this paper is an investigation of the COTS-based software development within a particular NASA environment, with an emphasis on the processes used. Fifteen projects using a COTS-based approach were studied and their actual process was documented. This process is evaluated to identify essential differences in comparison to traditional software development. The main differences, and the activities for which projects require more guidance, are requirements definition and COTS selection, high level design, integration and testing. Starting from these empirical observations, a new process and set of guidelines for COTS-based development are developed and briefly presented.
Keywords: Commercial off-the-shelf; Component-based; COTS; empirical study; Software development process

Cyclone: A safe dialect of C - Jim,T.; Morrisett,G.; Grossman,D.; Hicks, Michael W.; Cheney,J.; Wang, Y. (USENIX Annual Technical Conference, 2002)
Cyclone is a safe dialect of C. It has been designed from the ground up to prevent the buffer overflows, format string attacks, and memory management errors that are common in C programs, while retaining C's syntax and semantics. This paper examines safety violations enabled by C's design, and shows how Cyclone avoids them, without giving up C's hallmark control over low-level details such as data representation and memory management.

Detection of Cytotoxin-Hemolysin mRNA in Nonculturable Populations of Environmental and Clinical Vibrio Vulnificus Strains in Artificial Seawater - Fischer-Le Saux,Marion; Hervio-Heath,Dominique; Loaec,Solen; Rita R Colwell; Pommepuy,Monique (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2002)
The objective of this study was to develop a molecular detection method that better estimates the potential risk associated with the presence of Vibrio vulnificus. For that purpose, we applied seminested reverse transcription-PCR (RT-PCR) to viable but nonculturable (VBNC) populations of V. vulnificus and targeted the cytotoxin-hemolysin virulence gene vvhA. Three strains, two environmental, IF Vv10 and IF Vv18, and one clinical, C7184, were used in this study. Artificial seawater, inoculated with mid-log-phase cells, was maintained at 4°C. VBNC cells resulted after 3, 6, and 14 days for C7184, IF Vv18, and IF Vv10, respectively. Our data indicate that seminested RT-PCR is sensitive for the detection of vvhA mRNA in artificial seawater when exclusively nonculturable bacteria are present. This is the first report of the expression of a toxin gene in VBNC V. vulnificus. Moreover, vvhA transcripts were shown to persist in nonculturable populations over a 4.5-month period, with a progressive decline of the signal over time. This result indicates that special attention should be given to the presence of potentially pathogenic VBNC cells in environmental samples when assessing public health risk.

Effects of Global Climate on Infectious Disease: The Cholera Model - Lipp,Erin K.; Huq,Anwar; Rita R Colwell (Clinical Microbiology ReviewsClin. Microbiol. Rev., 2002)
Recently, the role of the environment and climate in disease dynamics has become a subject of increasing interest to microbiologists, clinicians, epidemiologists, and ecologists. Much of the interest has been stimulated by the growing problems of antibiotic resistance among pathogens, emergence and/or reemergence of infectious diseases worldwide, the potential of bioterrorism, and the debate concerning climate change. Cholera, caused by Vibrio cholerae, lends itself to analyses of the role of climate in infectious disease, coupled to population dynamics of pathogenic microorganisms, for several reasons. First, the disease has a historical context linking it to specific seasons and biogeographical zones. In addition, the population dynamics of V. cholerae in the environment are strongly controlled by environmental factors, such as water temperature, salinity, and the presence of copepods, which are, in turn, controlled by larger-scale climate variability. In this review, the association between plankton and V. cholerae that has been documented over the last 20 years is discussed in support of the hypothesis that cholera shares properties of a vector-borne disease. In addition, a model for environmental transmission of cholera to humans in the context of climate variability is presented. The cholera model provides a template for future research on climate-sensitive diseases, allowing definition of critical parameters and offering a means of developing more sophisticated methods for prediction of disease outbreaks.

Efficient Manipulation of Large Datasets on Heterogeneous Storage Systems - Beynon,Michael D.; Sussman, Alan; Kurc,Tahsin; Catalyurek,Umit; Saltz,Joel (Parallel and Distributed Processing Symposium, International, 2002)
In this paper we are concerned with the efficient use of a collection of disk-based storage systems and computing platforms in a heterogeneous setting for retrieving and processing large scientific datasets. We demonstrate, in the context of a data-intensive visualization application, how heterogeneity affects performance and show a set of optimization techniques that can be used to improve performance in a component-based framework. In particular, we examine the application of parallelism via transparent copies of application components in the pipelined processing of data.
Keywords: component-based frameworks; data-intensive computing; load balancing

Empirical findings in agile methods - Lindvall,M.; Basili, Victor R.; Boehm,B.; Costa,P.; Dangle,K.; Shull, F.; Tesoriero,R.; Williams,L.; Zelkowitz, Marvin V (Extreme Programming and Agile Methods—XP/Agile Universe 2002, 2002)
In recent years, the use of, interest in, and controversy about Agile methodologies have realized dramatic growth. Anecdotal evidence is rising regarding the effectiveness of agile methodologies in certain environments and for specified projects. However, collection and analysis of empirical evidence of this effectiveness and classification of appropriate environments for Agile projects has not been conducted. Researchers from four institutions organized an eWorkshop to synchronously and virtually discuss and gather experiences and knowledge from eighteen Agile experts spread across the globe. These experts characterized Agile Methods and communicated experiences using these methods on small to very large teams. They discussed the importance of staffing Agile teams with highly skilled developers. They shared common success factors and identified warning signs of problems in Agile projects. These and other findings and heuristics gathered through this valuable exchange can be useful to researchers and to practitioners as they establish an experience base for better decision making.

Evidence for a Plastid Origin of Plant Ethylene Receptor Genes - Mount, Stephen M.; Chang,Caren (Plant PhysiologyPlant Physiol., 2002)

Evidence-based model checking - Tan,L.; Cleaveland, Rance (Computer Aided Verification, 2002)

Executing Multiple Pipelined Data Analysis Operations in the Grid - Spencer,Matthew; Ferreira,Renato; Beynon,Michael; Kurc,Tahsin; Catalyurek,Umit; Sussman, Alan; Saltz,Joel (SC Conference, 2002)
Processing of data in many data analysis applications can be represented as an acyclic, coarse grain data flow, from data sources to the client. This paper is concerned with scheduling of multiple data analysis operations, each of which is represented as a pipelined chain of processing on data. We define the scheduling problem for effectively placing components onto Grid resources, and propose two scheduling algorithms. Experimental results are presented using a visualization application.

An experimental evaluation of linear and kernel-based methods for face recognition - Gupta, H.; Agrawala, Ashok K.; Pruthi, T.; Shekhar, C.; Chellapa, Rama (Applications of Computer Vision, 2002. (WACV 2002). Proceedings. Sixth IEEE Workshop on, 2002)
In this paper we present the results of a comparative study of linear and kernel-based methods for face recognition. The methods used for dimensionality reduction are Principal Component Analysis (PCA), Kernel Principal Component Analysis (KPCA), Linear Discriminant Analysis (LDA) and Kernel Discriminant Analysis (KDA). The methods used for classification are Nearest Neighbor (NN) and Support Vector Machine (SVM). In addition, these classification methods are applied on raw images to gauge the performance of these dimensionality reduction techniques. All experiments have been performed on images from UMIST Face Database.
Keywords: analysis; classification; component; discriminant; Face; image; Kernel; linear; Machine; nearest; neighbor; principal; recognition; Support; vector

Experimental Evaluation of the Unavailability Induced by a Group Membership Protocol - Joshi,Kaustubh; Michel Cukier; Sanders,William (Dependable Computing EDCC-4, 2002)
Group communication is an important paradigm for building highly available distributed systems. However, group membership operations often require the system to block message traffic, causing system services to become unavailable. This makes it important to quantify the unavailability induced by membership operations. This paper experimentally evaluates the blocking behavior of the group membership protocol of the Ensemble group communication system using a novel global-state-based fault injection technique. In doing so, we demonstrate how a layered distributed protocol such as the Ensemble group membership protocol can be modeled in terms of a state machine abstraction, and show how the resulting global state space can be used to specify fault triggers and define important measures on the system. Using this approach, we evaluate the cost associated with important states of the protocol under varying workload and group size. We also evaluate the sensitivity of the protocol to the occurrence of a second correlated crash failure during its operation.
Keywords: Computer science

Face recognition from video: a CONDENSATION approach - Zhou,Shaohua; Krueger, V.; Chellapa, Rama (Automatic Face and Gesture Recognition, 2002. Proceedings. Fifth IEEE International Conference on, 2002)
The aim of this work is to investigate how to exploit the temporal information in a video sequence for the task of face recognition. Following the approach in (Li and Chellappa, 2000), we propose a probabilistic model parameterized by a tracking state vector and a recognizing identity variable, simultaneously characterizing the kinematics and identity of humans. We then invoke a CONDENSATION (Isard and Blake, 1996) approach to provide a numerical solution to the model. Once the joint posterior distribution of the state vector and the identity variable is estimated, we marginalize it over the state vector to yield a robust estimate of the posterior distribution of the identity variable. Due to the propagation of identity and dynamics, a degeneracy in the posterior distribution of the identity variable is achieved to give improved recognition. This evolving behavior is characterized using changes in entropy. The effectiveness of this approach is illustrated using experimental results on low-resolution video data.
Keywords: algorithm; experimental; approach; Sequential; CONDENSATION; data; probabilistic; distribution; kinematics; low-resolution; importance; information; tracking; model; state; posterior; recognition; image; recognition; joint; resolution; image; results; face; sampling; sampling; probability; sequence; face; sequences; importance; state; vector; temporal; vector; video; video

Formal specification and verification of a group membership protocol for an intrusion-tolerant group communication system - Ramasamy,H. V.; Michel Cukier; Sanders,W. H. (2002)
We describe a group membership protocol that is part of an intrusion-tolerant group communication system, and present an effort to use formal tools to model and validate our protocol. We describe in detail the most difficult part of the validation exercise, which was the determination of the right level of abstraction of the protocol for formally specifying the protocol. The validation exercise not only formally showed that the protocol satisfies its correctness claims, but also provided information that will help us make the protocol more efficient without violating correctness.
Keywords: computer network reliability; distributed processing; distributed systems; fault tolerant computing; formal specification; formal verification; group membership protocol; intrusion-tolerant group communication system; PROMELA; Protocols

Fulfilling the promise of marine biotechnology - Rita R Colwell (Marine biotechnology in the twenty-first century: problems, promise, and productsMarine biotechnology in the twenty-first century: problems, promise, and products, 2002)

A generic approach to simultaneous tracking and verification in video - Li,Baoxin; Chellapa, Rama (Image Processing, IEEE Transactions on, 2002)
A generic approach to simultaneous tracking and verification in video data is presented. The approach is based on posterior density estimation using sequential Monte Carlo methods. Visual tracking, which is in essence a temporal correspondence problem, is solved through probability density propagation, with the density being defined over a proper state space characterizing the object configuration. Verification is realized through hypothesis testing using the estimated posterior density. In its most basic form, verification can be performed as follows. Given a measurement vector Z and two hypotheses H1 and H0, we first estimate posterior probabilities P(H0|Z) and P(H1|Z), and then choose the one with the larger posterior probability as the true hypothesis. Several applications of the approach are illustrated by experiments devised to evaluate its performance. The idea is first tested on synthetic data, and then experiments with real video sequences are presented, illustrating vehicle tracking and verification, human (face) tracking and verification, facial feature tracking, and image sequence stabilization.
Keywords: approach; Carlo; configuration; correspondence; data; density; density; estimated; estimation; evaluation; extraction; Face; facial; feature; generic; human; hypothesis; image; measurement; methods; Monte; object; performance; posterior; probability; probability; problem; processing; propagation; recognition; road; sequence; sequences; sequential; signal; space; stabilization; state; synthetic; temporal; testing; tracking; vector; vehicle; vehicles; verification; video; visual

Generic tools for verifying concurrent systems - Cleaveland, Rance; Sims,Steven T. (Science of Computer Programming, 2002)
Despite the enormous strides made in automatic verification technology over the past decade and a half, tools such as model checkers remain relatively underused in the development of software. One reason for this is that the bewildering array of specification and verification formalisms complicates the development and adoption by users of relevant tool support. This paper proposes a remedy to this state of affairs in the case of finite-state concurrent systems by describing an approach to developing customizable yet efficient verification tools.
Keywords: Model checking; Operational semantics; Process algebra; Specification; verification; Verification tools

Genome sequence and comparative analysis of the model rodent malaria parasite Plasmodium yoelii yoelii - Carlton,Jane M.; Angiuoli,Samuel V; Suh,Bernard B.; Kooij,Taco W.; Pertea,Mihaela; Silva,Joana C.; Ermolaeva,Maria D.; Allen,Jonathan E; Jeremy D Selengut; Koo,Hean L.; Peterson,Jeremy D.; Pop, Mihai; et al. (Nature, 2002)
Species of malaria parasite that infect rodents have long been used as models for malaria disease research. Here we report the whole-genome shotgun sequence of one species, Plasmodium yoelii yoelii, and comparative studies with the genome of the human malaria parasite Plasmodium falciparum clone 3D7. A synteny map of 2,212 P. y. yoelii contiguous DNA sequences (contigs) aligned to 14 P. falciparum chromosomes reveals marked conservation of gene synteny within the body of each chromosome. Of about 5,300 P. falciparum genes, more than 3,300 P. y. yoelii orthologues of predominantly metabolic function were identified. Over 800 copies of a variant antigen gene located in subtelomeric regions were found. This is the first genome sequence of a model eukaryotic parasite, and it provides insight into the use of such systems in the modelling of Plasmodium biology and disease.

Genomic profiles of clinical and environmental isolates of Vibrio cholerae O1 in cholera-endemic areas of Bangladesh - Zo,Y. G.; Rivera,I. N. G.; E. Russek-Cohen; Islam,M. S.; Siddique,A. K.; Yunus,M.; Sack,R. B.; Huq,A.; Rita R Colwell (Proceedings of the National Academy of Sciences, 2002)
Diversity, relatedness, and ecological interactions of toxigenic Vibrio cholerae O1 populations in two distinctive habitats, the human intestine and the aquatic environment, were analyzed. Twenty environmental isolates and 42 clinical isolates were selected for study by matching serotype, geographic location of isolation in Bangladesh, and season of isolation. Genetic profiling was done by enterobacterial repetitive intergenic consensus sequence–PCR, optimized for profiling by using the fully sequenced V. cholerae El Tor N16961 genome. Five significant clonal clusters of haplotypes were found from 57 electrophoretic types. Isolates from different areas or habitats intermingled in two of the five significant clusters. Frequencies of haplotypes differed significantly only between the environmental populations (exact test; P < 0.05). Analysis of molecular variance yielded a population genetic structure reflecting the differentiating effects of geographic area, habitat, and sampling time. Although a parameter confounding the latter differences explained 9% of the total molecular variance in the entire population (P < 0.01), the net effect of habitat and time could not be separated because of the small number of environmental isolates included in the study. Five subpopulations from a single area were determined, and from these we were able to estimate a relative differentiating effect of habitat, which was small compared with the effect of temporal change. In conclusion, the resulting population structure supports the hypothesis that spatial and temporal fluctuations in the composition of toxigenic V. cholerae populations in the aquatic environment can cause shifts in the dynamics of the disease.

A hierarchical approach for obtaining structure from two-frame optical flow - Liu,Haiying; Chellapa, Rama; Rosenfeld, A. (Motion and Video Computing, 2002. Proceedings. Workshop on, 2002)
A hierarchical iterative algorithm is proposed for extracting structure from two-frame optical flow. The algorithm exploits two facts: one is that in many applications, such as face and gesture recognition, the depth variation of the visible surface of an object in a scene is small compared to the distance between the optical center and the object; the other is that the time aliasing problem is alleviated at the coarse level for any two-frame optical flow estimate so that the estimate tends to be more accurate. A hierarchical representation for the relationship between the optical flow, depth, and the motion parameters is derived, and the resulting non-linear system is iteratively solved through two linear subsystems. At the coarsest level, the surface of the object tends to be flat, so that the inverse depth tends to be a constant, which is used as the initial depth map. Inverse depth and motion parameters are estimated by the two linear subsystems at each level and the results are propagated to finer levels. Error analysis and experiments using both computer-rendered images and real images demonstrate the correctness and effectiveness of our algorithm.
Keywords: algorithm; aliasing; analysis; computer-rendered; depth; depth; error; estimation; extraction; Face; feature; flow; gesture; hierarchical; image; images; inverse; iterative; methods; MOTION; nonlinear; optical; parameter; processing; real; recognition; sequences; signal; structure-from-motion; system; systems; TIME; two-frame; variation; video

High-level synthesis of DSP applications using adaptive negative cycle detection - Chandrachoodan,Nitin; Bhattacharyya, Shuvra S.; Liu,K. J.R (EURASIP J. Appl. Signal Process., 2002)
The problem of detecting negative weight cycles in a graph is examined in the context of the dynamic graph structures that arise in the process of high level synthesis (HLS). The concept of adaptive negative cycle detection is introduced, in which a graph changes over time and negative cycle detection needs to be done periodically, but not necessarily after every individual change. We present an algorithm for this problem, based on a novel extension of the well-known Bellman-Ford algorithm that allows us to adapt existing cycle information to the modified graph, and show by experiments that our algorithm significantly outperforms previous incremental approaches for dynamic graphs. In terms of applications, the adaptive technique leads to a very fast implementation of Lawlers algorithm for the computation of the maximum cycle mean (MCM) of a graph, especially for a certain form of sparse graph. Such sparseness often occurs in practical circuits and systems, as demonstrated, for example, by the ISCAS 89/93 benchmarks. The application of the adaptive technique to design-space exploration (synthesis) is also demonstrated by developing automated search techniques for scheduling iterative data-flow graphs.
Keywords: adaptive performance estimation; dynamic graphs; maximum cycle mean; negative cycle detection

How young can our design partners be - Farber,A.; Druin, Allison; Chipman,G.; Julian,D.; Somashekhar,S. (Proceedings of the Participatory Design Conference, 2002)

Identification of humans using gait - Kale, A.; Rajagopalan, AN; Cuntoor, N.; Krueger, V.; Chellapa, Rama (IEEE Transactions on Image Processing, 2002)
We propose a view-based approach to recognize humans from their gait. Two different imagefeatures have been considered: the width of the outer contour of the binarized silhouette of the walking person and the entire binary silhouette itself. To obtain the observation vector from the image features we employ two different methods. In the first method referred to as the indirect approach, the high-dimensional image feature is transformed to a lower-dimensional space by generating what we call the Frame to Exemplar (FED) distance. The FED vector captures both structural and dynamic traits of each individual. For compact and effective gait representation and recognition, the gait information in the FED vector sequences is captured in a hidden Markov model (HMM). In the second method referred to as the direct approach, we work with the feature vector directly (as opposed to computing the FED) and train an HMM. We estimate the HMM parameters (specifically the observation probability B) based on the distance between the exemplars and the image features. In this way we avoid learning high-dimensional probability density functions. The statistical nature of the HMM lends overall robustness to representation and recognition. The performance of the methods is illustrated using several databases.

Image-based face recognition: Issues and methods - Zhao, W.Y.; Chellapa, Rama (Image recognition and classification: algorithms, systems, and applicationsImage recognition and classification: algorithms, systems, and applications, 2002)

Improving Web-based civic information access: a case study of the 50 US states - Ceaparu,I.; Shneiderman, Ben (2002 International Symposium on Technology and Society, 2002. (ISTAS'02), 2002)
An analysis of the home pages of all fifty US states reveals great variety in key design features that influence efficacy. Some states had excessively large byte counts that would slow users connected by commonly-used 56 K modems. Many web sites had low numbers of or poorly organized links that would make it hard for citizens to find what they were interested in. Features such as search boxes, privacy policies, online help, or contact information need to be added by several states. Our analysis concludes with ten recommendations and finds many further opportunities for individual states to improve their Websites. However still greater benefits will come through collaboration among the states that would lead to consistency, appropriate tagging, and common tools.
Keywords: Computer aided software engineering; Computer science; contact information; Educational institutions; government data processing; Guidelines; home page design features; information resources; Laboratories; Modems; Navigation; online help; privacy; privacy policies; search boxes; Tagging; Uniform resource locators; US states; USA; User interfaces; Web sites; Web-based civic information access

In vitro adhesion to human cells by viable but nonculturable Enterococcus faecalis - Pruzzo,C.; Tarsi,R.; Lleò,M. M.; Signoretto,C.; Zampini,M.; Rita R Colwell; Canepari,P. (Current microbiology, 2002)
The ability of viable but nonculturable (VBNC) Enterococcus faecalis to adhere to Caco-2 and Girardi heart cultured cells and to urinary tract epithelial cells (ECs) was studied. Enterococci were harvested during the vegetative growth phase (early exponential and stationary), in the VBNC state, and after recovery of the ability to divide. VBNC bacteria maintained their adherence capability but the efficiency of attachment was reduced by about 50 to 70%, depending on the target cell employed. The decrease was transient, since enterococci that regained their culturability showed adherence values similar to those observed for actively growing cells. Analysis of the invasive properties of E. faecalis revealed that the VBNC state caused a decrease in the number of bacteria that entered the cultured HEK cells as a result of the reduction in the number of adhering bacteria. These results highlight the importance of studies of the VBNC phenomenon, with respect to both microbial survival in the environment and the impact on human health.

In Web we trust: establishing strategic trust among online customers - Ceaparu,I.; Demner,D.; Hung,E.; Zhao,H.; Shneiderman, Ben (E-Service: new directions in theory and practice, 2002)
Electronic commerce (e-commerce) provides an important chance for established large companies to gain more customers as well as for new small companies to have a good start and rapid growth. However, establishing trust between customers and companies through web interface, a key component of successful e-service, is not as easy as through human-buyer-human-seller interaction. In the past few years, a number of experiments have been conducted in order to determine the factors that influence customers' trust in online businesses. The goal of our experiment was to establish which features that appear on commercial websites are trust-inducing. Our study focused on three independent variables: customer service (limited and extensive), testimonial (self and external) and security features representation (graphics and text). We designed the homepages of eight web sites with all combinations of treatments of the three independent variables. Each of the 52 subjects reviewed all the eight homepages and gave them a relative rank of trustworthiness. After the experiment subjects answered additional e-trust related questions. The experiment results and the survey support the belief that specific customer service commitments, third party testimonials and graphic security representations are important in establishing strategic trust among on-line customers.

Level of Detail for 3D Graphics - Luebke, David; Watson, Benjamin; Cohen, Jonathan D.; Reddy, Martin; Varshney, Amitabh (Elsevier Science Inc., 2002)
Level of detail (LOD) techniques are increasingly used by professional real-time developers to strike the balance between breathtaking virtual worlds and smooth, flowing animation. Level of Detail for 3D Graphics brings together, for the first time, the mechanisms, principles, practices, and theory needed by every graphics developer seeking to apply LOD methods.Continuing advances in level of detail management have brought this powerful technology to the forefront of 3D graphics optimization research. This book, written by the very researchers and developers who have built LOD technology, is both a state-of-the-art chronicle of LOD advances and a practical sourcebook, which will enable graphics developers from all disciplines to apply these formidable techniques to their own work.

Optimal edge-based shape detection - Moon, H.; Chellapa, Rama; Rosenfeld, A. (Image Processing, IEEE Transactions on, 2002)
We propose an approach to accurately detecting two-dimensional (2-D) shapes. The cross section of the shape boundary is modeled as a step function. We first derive a one-dimensional (1-D) optimal step edge operator, which minimizes both the noise power and the mean squared error between the input and the filter output. This operator is found to be the derivative of the double exponential (DODE) function, originally derived by Ben-Arie and Rao (1994). We define an operator for shape detection by extending the DODE filter along the shape's boundary contour. The responses are accumulated at the centroid of the operator to estimate the likelihood of the presence of the given shape. This method of detecting a shape is in fact a natural extension of the task of edge detection at the pixel level to the problem of global contour detection. This simple filtering scheme also provides a tool for a systematic analysis of edge-based shape detection. We investigate how the error is propagated by the shape geometry. We have found that, under general assumptions, the operator is locally linear at the peak of the response. We compute the expected shape of the response and derive some of its statistical properties. This enables us to predict both its localization and detection performance and adjust its parameters according to imaging conditions and given performance specifications. Applications to the problem of vehicle detection in aerial images, human facial feature detection, and contour tracking in video are presented.
Keywords: 1D; 2D; aerial; analysis; boundary; conditions; contour; cross; detection; DODE; double; edge; edge-based; error; error; exponential; extraction; facial; feature; filter; filter; Filtering; function; geometry; global; human; images; imaging; localization; mean; methods; NOISE; operator; optimal; optimisation; output; performance; pixel; power; propagation; properties; section; SHAPE; square; squared; statistical; step; theory; tracking; two-dimensional; vehicle; video

Passive replication schemes in AQuA - Ren,Yansong; Rubel,P.; Seri,M.; Michel Cukier; Sanders,W. H.; Courtney,T. (2002)
Building large-scale distributed object-oriented systems that provide multidimensional quality of service (QoS) in terms of fault tolerance, scalability, and performance is challenging. In order to meet this challenge, we need an architecture that can ensure that applications' requirements can be met while providing reusable technologies and software solutions. This paper describes techniques, based on the AQuA architecture, that enhance the applications' dependability and scalability by introducing two types of group members and a novel passive replication scheme. In addition, we describe how to make the management structure itself dependable by using the passive replication scheme. Finally, we provide performance measurements for the passive replication scheme.
Keywords: AQuA architecture; distributed object management; Fault tolerance; group members; large-scale distributed object-oriented systems; management structure; multidimensional quality of service; passive replication scheme; performance measurements; reusable technologies; scalability; software fault tolerance; software performance evaluation; software reusability; software solutions

Performance analysis of a simple vehicle detection algorithm - Moon, H.; Chellapa, Rama; Rosenfeld, A. (Image and Vision Computing, 2002)
We have performed an end-to-end analysis of a simple model-based vehicle detection algorithm for aerial parking lot images. We constructed a vehicle detection operator by combining four elongated edge operators designed to collect edge responses from the sides of a vehicle. We derived the detection and localization performance of this algorithm, and verified them by experiments. Performance degradation due to different camera angles and illuminations was also examined using simulated images. Another important aspect of performance characterization — whether and how much prior information about the scene improves performance — was also investigated. As a statistical diagnostic tool for the detection performance, a computational approach employing bootstrap was used.
Keywords: Aerial image; Bootstrap; empirical evaluation; Performance analysis; Vehicle detection

Performance evaluation of a probabilistic replica selection algorithm - Krishnamurthy, S.; Sanders,W. H.; Michel Cukier (2002)
When executing time-sensitive distributed applications, a middleware that provides dependability and timeliness is faced with the important problem of preventing timing failures both under normal conditions and when the quality of service is degraded due to replica failures and transient overload on the server. To address this problem, we have designed a probabilistic model-based replica selection algorithm that allows a middleware to choose a set of replicas to service a client based on their ability to meet a client's timeliness requirements. This selection is done based on the prediction made by a probabilistic model that uses the performance history of replicas as inputs. In this paper, we describe the experiments we have conducted to evaluate the ability of this dynamic selection algorithm to meet a client's timing requirements, and compare it with that of a static and round-robin selection scheme under different scenarios
Keywords: client-server systems; Dependability; distributed object management; dynamic selection algorithm; Middleware; probabilistic model; probabilistic model-based replica selection algorithm; probability; quality of service; real-time systems; replica failures; round-robin selection scheme; static scheme; time-sensitive distributed applications; timeliness; timing failures; transient overload

Performance evaluation of a QoS-aware framework for providing tunable consistency and timeliness - Krishnamurthy, S.; Sanders,W. H.; Michel Cukier (2002)
Strong replica consistency models ensure that the data delivered by a replica always includes the latest updates, although this may result in poor response times. On the other hand, weak replica consistency models provide quicker access to information, but do not usually provide guarantees about the degree of staleness in the data they deliver. In order to support emerging distributed applications that are characterized by high concurrency demands, an increasing shift towards dynamic content, and timely delivery, we need quality of service models that allow us to explore the intermediate space between these two extreme approaches to replica consistency. Further, for better support of time-sensitive applications that can tolerate relaxed consistency in exchange for better responsiveness, we need to understand how the desired level of consistency affects the timeliness of a response. The QoS model we have developed to realize these objectives considers both timeliness and consistency, and treats consistency along two dimensions: order and staleness. We evaluate experimentally the framework we have developed to study the timeliness/consistency tradeoffs for replicated services and present experimental results that compare these tradeoffs in the context of sequential and FIFO ordering.
Keywords: client-server systems; Computer networks; CORBA-based middleware; distributed applications; distributed object management; Network servers; QoS; quality of service; replica consistency; replicated services; server replicas; timeliness

Persistent caching in a multiple query optimization framework - Andrade,H.; Kurc, T.; Catalyurek,U.; Sussman, Alan; Saltz, J. (Proceedings of the 6th Workshop on Languages, Compilers, and Run-Time Systems for Scalable Computers, 2002)
This paper focuses on persistent caching in multi-client en-vironments, which aims to improve the performance of a data server by caching on disk query results that can be expensive to produce. We present and evaluate extensions to an existing multi-query optimization framework, called MQO, to incorporate persistent caching capabilities.

Phylogenetic analysis based on 18S ribosomal RNA gene sequences supports the existence of class Polyacanthocephala (Acanthocephala) - García-Varela,M; Cummings, Michael P.; Pérez-Ponce de León,G.; Gardner,S. L; Laclette,J. P (Mol Phylogenet Evol, 2002)
Members of phylum Acanthocephala are parasites of vertebrates and arthropods and are distributed worldwide. The phylum has traditionally been divided into three classes, Archiacanthocephala, Palaeacanthocephala, and Eoacanthocephala; a fourth class, Polyacanthocephala, has been recently proposed. However, erection of this new class, based on morphological characters, has been controversial. We sequenced the near complete 18S rRNA gene of Polyacanthorhynchus caballeroi (Polyacanthocephala) and Rhadinorhynchus sp. (Palaeacanthocephala); these sequences were aligned with another 21 sequences of acanthocephalans representing the three widely recognized classes of the phylum and with 16 sequences from outgroup taxa. Phylogenetic relationships inferred by maximum-likelihood and maximum-parsimony analyses showed Archiacanthocephala as the most basal group within the phylum, whereas classes Polyacanthocephala + Eoacanthocephala formed a monophyletic clade, with Palaeacanthocephala as its sister group. These results are consistent with the view of Polyacanthocephala representing an independent class within Acanthocephala.

Physical Programming: Designing Tools for Children to Create Physical Interactive - Montemayor,J.; Druin, Allison; Farber,A.; Simms,S.; Churaman,W. (Proceedings: SIGCHI, 2002)

Probabilistic Human Recognition from Video - Zhou,Shaohua; Chellapa, Rama (Computer Vision — ECCV 2002Computer Vision — ECCV 2002, 2002)
This paper presents a method for incorporating temporal information in a video sequence for the task of human recognition. A time series state space model, parameterized by a tracking state vector and a recognizing identity variable , is proposed to simultaneously characterize the kinematics and identity. Two sequential importance sampling (SIS) methods, a brute-force version and an efficient version, are developed to provide numerical solutions to the model. The joint distribution of both state vector and identity variable is estimated at each time instant and then propagated to the next time instant. Marginalization over the state vector yields a robust estimate of the posterior distribution of the identity variable. Due to the propagation of identity and kinematics, a degeneracy in posterior probability of the identity variable is achieved to give improved recognition. This evolving behavior is characterized using changes in entropy . The effectiveness of this approach is illustrated using experimental results on low resolution face data and upper body data.

Probabilistic recognition of human faces from video - Chellapa, Rama; Kruger, V.; Zhou,Shaohua (Image Processing. 2002. Proceedings. 2002 International Conference on, 2002)
Most present face recognition approaches recognize faces based on still images. We present a novel approach to recognize faces in video. In that scenario, the face gallery may consist of still images or may be derived from a videos. For evidence integration we use classical Bayesian propagation over time and compute the posterior distribution using sequential importance sampling. The probabilistic approach allows us to handle uncertainties in a systematic manner. Experimental results using videos collected by NIST/USF and CMU illustrate the effectiveness of this approach in both still-to-video and video-to-video scenarios with appropriate model choices.
Keywords: Bayes; Bayesian; CMU; distribution; Face; faces; gallery; handling; human; image; images; importance; likelihood; methods; NIST/USF; observation; posterior; probabilistic; probability; processing; propagation; recognition; sampling; sequential; signal; still; Still-to-video; Uncertainty; video; Video-to-video

Probabilistic validation of intrusion tolerance - Sanders,W. H.; Michel Cukier; Webber,F.; Pal,P.; Watro,R. (2002)

Processing large-scale multi-dimensional data in parallel and distributed environments - Beynon,Michael; Chang,Chialin; Catalyurek,Umit; Kurc,Tahsin; Sussman, Alan; Andrade,Henrique; Ferreira,Renato; Saltz,Joel (Parallel Computing, 2002)
Analysis of data is an important step in understanding and solving a scientific problem. Analysis involves extracting the data of interest from all the available raw data in a dataset and processing it into a data product. However, in many areas of science and engineering, a scientist's ability to analyze information is increasingly becoming hindered by dataset sizes. The vast amount of data in scientific datasets makes it a difficult task to efficiently access the data of interest, and manage potentially heterogeneous system resources to process the data. Subsetting and aggregation are common operations executed in a wide range of data-intensive applications. We argue that common runtime and programming support can be developed for applications that query and manipulate large datasets. This paper presents a compendium of frameworks and methods we have developed to support efficient execution of subsetting and aggregation operations in applications that query and manipulate large, multi-dimensional datasets in parallel and distributed computing environments.
Keywords: Data-intensive applications; Distributed computing; Multi-dimensional datasets; PARALLEL PROCESSING; Runtime systems

Purification and properties of the extracellular lipase, LipA, of Acinetobacter sp. RAG‐1 - Snellman,Erick A.; Sullivan,Elise R.; Rita R Colwell (European Journal of Biochemistry, 2002)
An extracellular lipase, LipA, extracted from Acinetobacter sp. RAG-1 grown on hexadecane was purified and properties of the enzyme investigated. The enzyme is released into the growth medium during the transition to stationary phase. The lipase was harvested from cells grown to stationary phase, and purified with 22% yield and > 10-fold purification. The protein demonstrates little affinity for anion exchange resins, with contaminating proteins removed by passing crude supernatants over a Mono Q column. The lipase was bound to a butyl Sepharose column and eluted in a Triton X-100 gradient. The molecular mass (33 kDa) was determined employing SDS/PAGE. LipA was found to be stable at pH 5.8–9.0, with optimal activity at 9.0. The lipase remained active at temperatures up to 70 °C, with maximal activity observed at 55 °C. LipA is active against a wide range of fatty acid esters of p-nitrophenyl, but preferentially attacks medium length acyl chains (C6, C8). The enzyme demonstrates hydrolytic activity in emulsions of both medium and long chain triglycerides, as demonstrated by zymogram analysis. RAG-1 lipase is stabilized by Ca2+, with no loss in activity observed in preparations containing the cation, compared to a 70% loss over 30 h without Ca2+. The lipase is strongly inhibited by EDTA, Hg2+, and Cu2+, but shows no loss in activity after incubation with other metals or inhibitors examined in this study. The protein retains more than 75% of its initial activity after exposure to organic solvents, but is rapidly deactivated by pyridine. RAG-1 lipase offers potential for use as a biocatalyst.
Keywords: Acinetobacter sp. RAG‐1; LipA; lipase; protein purification; zymogram

Quantifying the cost of providing intrusion tolerance in group communication systems - Ramasamy,H. V.; Pandey,P.; Lyons,J.; Michel Cukier; Sanders,W. H. (2002)
Group communication systems that provide consistent group membership and reliable, ordered multicast properties in the presence of faults resulting from malicious intrusions have not been analyzed extensively to quantify the cost of tolerating these intrusions. This paper attempts to quantify this cost by presenting results from an experimental evaluation of three new intrusion-tolerant microprotocols that have been added to an existing crash-fault-tolerant group communication system. The results are analyzed to identify the parts that contribute the most overhead during provision of intrusion tolerance at the group communication system level.
Keywords: consistent group membership; crash-fault-tolerant group communication system; cryptography; finite state machines; groupware; intrusion-tolerant microprotocols; malicious intrusions; multicast communication; reliable ordered multicast properties; security of data; Transport protocols

Quasi-invariants for human action representation and recognition - Parameswaran, V.; Chellapa, Rama (Pattern Recognition, 2002. Proceedings. 16th International Conference on, 2002)
Although human action recognition has been the subject of much research in the past, the issue of viewpoint invariance has received scarce attention. In this paper, we present an approach to detect human action with a high tolerance to viewpoint change. Canonical body poses are modeled in a view invariant manner to enable detection from a general viewpoint. While there exist no invariants for 3D to 2D projection, there exists a wealth of techniques in 2D invariance that can be used to advantage in 3D to 2D projection. We employ 2D invariants to recognize canonical poses of the human body leading to an effective way to represent and recognize human action which we evaluate theoretically and experimentally on 2D projections of publicly available human motion capture data.
Keywords: 2D; action; analysis; body; canonical; change; human; image; invariance; MOTION; poses; quasi-invariants; recognition; representation; tolerance; viewpoint

Reconstructing Images of Bar Codes for Construction Site Object Recognition - Gilsinn,David E.; Cheok,Geraldine S.; O'Leary, Dianne P. (Proceedings of the 19th International Symposium on Automation and Robotics in Construction, 2002)

Region-based memory management in cyclone - Grossman,Dan; Morrisett,Greg; Jim,Trevor; Hicks, Michael W.; Wang,Yanling; Cheney,James (SIGPLAN Not., 2002)
Cyclone is a type-safe programming language derived from C. The primary design goal of Cyclone is to let programmers control data representation and memory management without sacrificing type-safety. In this paper, we focus on the region-based memory management of Cyclone and its static typing discipline. The design incorporates several advancements, including support for region subtyping and a coherent integration with stack allocation and a garbage collector. To support separate compilation, Cyclone requires programmers to write some explicit region annotations, but a combination of default annotations, local type inference, and a novel treatment of region effects reduces this burden. As a result, we integrate C idioms in a region-based framework. In our experience, porting legacy C to Cyclone has required altering about 8% of the code; of the changes, only 6% (of the 8%) were region annotations.

A robust algorithm for probabilistic human recognition from video - Zhou,Shaohua; Chellapa, Rama (Pattern Recognition, 2002. Proceedings. 16th International Conference on, 2002)
Human recognition from video requires solving the two tasks, recognition and tracking, simultaneously. This leads to a parameterized time series state space model, representing both motion and identity of the human. Sequential Monte Carlo (SMC) algorithms, like Condensation, can be developed to offer numerical solutions to this model. However in outdoor environments, the solution is more likely to diverge from the foreground, causing failures in both recognition and tracking. In this paper we propose an approach for tackling this problem by incorporating the constraint of temporal continuity in the observations. Experimental results demonstrate improvements over its Condensation counterpart.
Keywords: algorithm; algorithms; Carlo; continuity; human; image; methods; model; Monte; parameterized; probabilistic; recognition; robust; sequential; series; series; space; state; state-space; temporal; TIME

Simple Procedure for Rapid Identification of Vibrio Cholerae from the Aquatic Environment - Choopun,Nipa; Louis,Valérie; Huq,Anwar; Rita R Colwell (Applied and Environmental MicrobiologyAppl. Environ. Microbiol., 2002)
Biochemical tests commonly used to screen for Vibrio cholerae in environmental samples were evaluated, and we found that a combination of alkaline peptone enrichment followed by streaking on thiosulfate citrate bile salts sucrose agar and testing for arginine dihydrolase activity and esculin hydrolysis was an effective rapid technique to screen for aquatic environmental V. cholerae. This technique provided 100% sensitivity and ≥70% specificity.

State of the art in data representation for visualization - Chen,B.; Kaufman,A.; Mueller,K.; Varshney, Amitabh (IEEE Visualization Tutorial, 2002)

Structure from Motion/Stereoscopic Vision/Surface Geometry/Shape-Bayesian Self-Calibration of a Moving Camera - Qian, G.; Chellapa, Rama (Lecture Notes in Computer Science, 2002)

Towards a criterion for evaluating the quality of 3D reconstructions - Roy Chowdhury,Amit K.; Chellapa, Rama (Acoustics, Speech, and Signal Processing (ICASSP), 2002 IEEE International Conference on, 2002)
Even though numerous algorithms exist for estimating the structure of a scene from its video, the solutions obtained are often of unacceptable quality. To overcome some of the deficiencies, many application systems rely on processing more information than necessary with the hope that the redundancy will help improve the quality. This raises the question about how the accuracy of the solution is related to the amount of information processed by the algorithm. Can we define the accuracy of the solution precisely enough that we automatically recognize situations where the quality of the data is so bad that even a large number of additional observations will not yield the desired solution? This paper proposes an information theoretic criterion for evaluating the quality of a 3D reconstruction in terms of the statistics of the observed parameters (i.e. the image correspondences). The accuracy of the reconstruction is judged by considering the change in mutual information (or equivalently the conditional differential entropy) between a scene and its reconstructions and its effectiveness is shown through simulations.

Triggered message sequence charts - Sengupta,Bikram; Cleaveland, Rance (ACM SIGSOFT Software Engineering Notes, 2002)

Two-frame multi-scale optical flow estimation using wavelet decomposition - Liu,Haiying; Rosenfeld,Azriel; Chellapa, Rama (Acoustics, Speech, and Signal Processing (ICASSP), 2002 IEEE International Conference on, 2002)
A multi-scale algorithm using wavelet decomposition is proposed to estimate dense optical flow using only two frames. Hierarchical image representation by wavelet decomposition is used to exploit the assumption of local rigid motion in a new multi-scale framework. It is shown that if a wavelet basis with one vanishing moment is carefully selected, we can get hierarchical images, edges, and comers from the wavelet decomposition. Based on this result, all the components of the wavelet decomposition are used to estimate relatively accurate optical flow even under the inadequate image sampling condition, and overcome the #x201C;flattening-out #x201D; problem in traditional pyramid methods, which produce high errors when low-texture regions become flat at coarse levels due to blurring. Local affine transforms are also used to speed up flow estimation. Experiments on different types of image sequences together with quantitative and qualitative comparisons with several other optical flow methods are given to demonstrate the effectiveness and robustness of our algorithm.

Understanding Machine Performance in the Context of Human Performance for Multi-document Summarization - Schlesinger,J.D.; Okurowski,M. E.; Conroy,J.M.; O'Leary, Dianne P.; Taylor,A.; Hobbs,J.; Wilson,H. T. (DUC 02 Conference ProceedingsDUC 02 Conference Proceedings, 2002)
We present a discussion of our summarization algorithm -- both single and multi-document -- along with a discussion of the evaluation experiments we have undertaken, what we have learned from them, and how we intend to utilize this information.

View-Based Recognition of Military Vehicles in Ladar Imagery Using CAD Model Matching - Der, S.Z.; Zheng,Q.; Redman, B.; Chellapa, Rama; Mahmoud, H. (OPTICAL ENGINEERING-NEW YORK-MARCEL DEKKER INCORPORATED-, 2002)

A voyage of discovery: cholera, climate and complexity - Rita R Colwell (Environmental Microbiology, 2002)

Wavelength rerouting in optical networks, or the Venetian Routing problem - Caprara,Alberto; Italiano,Giuseppe F.; Mohan,G.; Panconesi,Alessandro; Srinivasan, Aravind (Journal of Algorithms, 2002)
Wavelength rerouting has been suggested as a viable and cost-effective method to improve the blocking performance of wavelength-routed wavelength-division multiplexing (WDM) networks. This method leads to the following combinatorial optimization problem, dubbed Venetian Routing. Given a directed multigraph G along with two vertices s and t and a collection of pairwise arc-disjoint paths, we wish to find an st-path which arc-intersects the smallest possible number of the given paths. In this paper we prove the computational hardness of this problem even in various special cases, and present several approximation algorithms for its solution. In particular we show a non-trivial connection between Venetian Routing and Label Cover.
Keywords: Approximation algorithms; Label Cover; Optical networks; Shortest paths; Wavelength rerouting; Wavelength-division multiplexing

What we have learned about fighting defects - Shull, F.; Basili, Victor R.; Boehm,B.; Brown,A. W; Costa,P.; Lindvall,M.; Port,D.; Rus,I.; Tesoriero,R.; Zelkowitz, Marvin V (Software Metrics, 2002. Proceedings. Eighth IEEE Symposium on, 2002)
The Center for Empirically Based Software Engineering helps improve software development by providing guidelines for selecting development techniques, recommending areas for further research, and supporting software engineering education. A central activity toward achieving this goal has been the running of "e- Workshops" that capture expert knowledge with a minimum of overhead effort to formulate heuristics on a particular topic. The resulting heuristics are a useful summary of the current state of knowledge in an area based on expert opinion. This paper discusses the results to date of a series of e-Workshops on software defect reduction. The original discussion items are presented along with an encapsulated summary of the expert discussion. The reformulated heuristics can be useful both to researchers (for pointing out gaps in the current state of the knowledge requiring further investigation) and to practitioners (for benchmarking or setting expectations about development practices).
Keywords: based; Center; Computer; defect; development; education; electronic; Empiric; engineering; engineering; eWorkshops; for; heuristics; reduction; Science; software; workshops

Wide baseline image registration using prior information - Chowdhury, AM; Chellapa, Rama; Keaton, T. (Multimedia Signal Processing, 2002 IEEE Workshop on, 2002)
Establishing correspondence between features in two images of the same scene taken from different viewing angles in a challenging problem in image processing and computer vision. However, its solution is an important step in many applications like wide baseline stereo, 3D model alignment, creation of panoramic views etc. In this paper, we propose a technique for registration of two images of a face obtained from different viewing angles. We show that prior information about the general characteristics of a face obtained from video sequences of different faces can be used to design a robust correspondence algorithm. The method works by matching 2D shapes of the different features of the face. A doubly stochastic matrix, representing the probability of match between the features, is derived using the Sinkhorn normalization procedure. The final correspondence is obtained by minimizing the probability of error of a match between the entire constellations of features in the two sets, thus taking into account the global spatial configuration of the features. The method is applied for creating holistic 3D models of a face from partial representations. Although this paper focuses primarily on faces, the algorithm can also be used for other objects with small modifications.
Keywords: 2D; 3D; algorithm; alignment; angles; baseline; Computer; configuration; constellation; correspondence; creation; doubly; error; extraction; Face; feature; global; holistic; image; images; matching; matrix; model; models; normalization; panoramic; probability; procedure; processes; processing; registration; robust; sequences; SHAPE; signal; Sinkhorn; spatial; statistics; stereo; Stochastic; video; view; viewing; vision; wide

An adaptive algorithm for tolerating value faults and crash failures - Ren,Yansong; Michel Cukier; Sanders,W. H. (Parallel and Distributed Systems, IEEE Transactions on, 2001)
The AQuA architecture provides adaptive fault tolerance to CORBA applications by replicating objects and providing a high-level method that an application can use to specify its desired level of dependability. This paper presents the algorithms that AQUA uses, when an application's dependability requirements can change at runtime, to tolerate both value faults in applications and crash failures simultaneously. In particular, we provide an active replication communication scheme that maintains data consistency among replicas, detects crash failures, collates the messages generated by replicated objects, and delivers the result of each vote. We also present an adaptive majority voting algorithm that enables the correct ongoing vote while both the number of replicas and the majority size dynamically change. Together, these two algorithms form the basis of the mechanism for tolerating and recovering from value faults and crash failures in AQuA
Keywords: active replication communication; adaptive algorithm; adaptive fault tolerance; adaptive majority voting algorithm; AQuA architecture; client-server systems; CORBA; crash failures; data consistency; data integrity; Dependability; distributed object management; fault tolerant computing; objects replication; value faults

Adaptive negative cycle detection in dynamic graphs - Chandrachoodan,N.; Bhattacharyya, Shuvra S.; Liu,K. J.R (Circuits and Systems, 2001. ISCAS 2001. The 2001 IEEE International Symposium on, 2001)

Algorithms for facility location problems with outliers - Charikar,Moses; Khuller, Samir; Mount, Dave; Narasimhan,Giri (Proceedings of the twelfth annual ACM-SIAM symposium on Discrete algorithms, 2001)
Facility location problems are traditionally investigated with the assumption that all the clients are to be provided service. A significant shortcoming of this formulation is that a few very distant clients, called outliers, can exert a disproportionately strong influence over the final solution. In this paper we explore a generalization of various facility location problems (K-center, K-median, uncapacitated facility location etc) to the case when only a specified fraction of the customers are to be served. What makes the problems harder is that we have to also select the subset that should get service. We provide generalizations of various approximation algorithms to deal with this added constraint.

Analysis of attacks on SDMI audio watermarks - M. Wu; Craver,S.; Felten,E.W.; Liu,B. (Acoustics, Speech, and Signal Processing, 2001. Proceedings. (ICASSP '01). 2001 IEEE International Conference on, 2001)
This paper explains and analyzes the successful attacks submitted by the authors on four audio watermark proposals during a 3-week SDMI public challenge. Our analysis points out some weaknesses in the watermark techniques currently under SDMI consideration and suggests directions for further improvement. The paper also discusses the framework and strategies for analyzing the robustness and security of watermarking systems as well as the difficulty, uniqueness, and unrealistic expectations of the attack setup
Keywords: attacks; watermark; audio; coding; copy; digital; encapsulation; Initiative; attack; Music; protection; data; SDMI; setup; robustness; security; successful; watermarks; Secure; weaknesses; audio

Assessment of the k-epsilon turbulence model for compressible flows using direct simulation data - Sinha,K.; Candler,G. V; Martin, M.P (39th AIAA Aerospace Sciences Meeting and Exhibit, 2001)
We evaluate the k-epsilon turbulence model using direct numerical simulation (DNS) data of a Mach 4 boundary layer. We find that the low Reynolds number damping functions for the Reynolds stress must be corrected by the density ratio to match the DNS data. We present the budget of the k equation and assess the modeling of the various source terms. The models for all the source terms, except for the production and dilatational dissipation terms, are found to be adequate. Finally, we present the solenoidal dissipation rate equation and compute its budget using the boundary layer data. We compare this equation with the dissipation rate equation in an incompressible flow to show the equivalence between the two equations. This is the basis for modeling the solenoidal dissipation equation. However, an additional term in the equation due to variation of fluid viscosity needs to be modeled.

Attentive toys - Haritaoglu,I.; Cozzi,A.; Koons,D.; Flickner,M.; Zotkin,Dmitry N; Yacoob,Yaser (International Conference on Multimedia and Expo, 2001)

Automated Validation of Software Models - Sims,Steve; Cleaveland, Rance; Butts,Ken; Ranville,Scott (Automated Software Engineering, International Conference on, 2001)
This paper describes the application of an automated verification tool to a software model developed at Ford. Ford already has in place an advanced model-based software development framework that employs the Matlab?, Simulink?, and Stateflow? modeling tools. During this project we applied the invariant checker Salsa to a Simulink?/ Stateflow? model of automotive software to check for nondeterminism, missing cases, dead code, and redundant code. During the analysis, a number of anomalies were detected that had not been found during manual review. We argue that the detection and correction of these problems demonstrates a cost-effective application of formal verification that elevates our level of confidence in the model.

Building an Experience Base for Software Engineering: A report on the first CeBASE eWorkshop - Basili, Victor R.; Tesoriero,R.; Costa,P.; Lindvall,M.; Rus,I.; Shull, F.; Zelkowitz, Marvin V (Product Focused Software Process Improvement, 2001)
New information is obtained by research and disseminated by papers in conferences and journals. The synthesis of knowledge depends upon social discourse among the experts in a given domain to discuss the impact of this new information. Meetings among such experts are, however, expensive and time consuming. In this paper we discuss the organization of CeBASE, a center whose goal is the collection and dissemination of empirically-based software engineering knowledge, and the concept of the online workshop or eWorkshop as a way to use the Internet to minimize the needs of face-to-face meetings. We discuss the design of our eWorkshop and give the results of one eWorkshop that discussed the impact of defect reduction strategies.We want to thank Barry Boehm, Scott Henninger, Rayford Vaughn, Winsor Brown, Dan Port and Michael Frey as well as all participants for their contribution to the success of the eWorkshop. We also want to thank students at USC and UMD for their contribution in testing the system and Jennifer Dix for proof reading this paper.

CLEF experiments at Maryland: Statistical stemming and backoff translation - Oard, Douglas; Levow,G.A.; Cabezas,C. (Cross-Language Information Retrieval and Evaluation, 2001)

Cyclone User's Manual, Version 0.1. 3 - Grossman,D.; Morrisett,G.; Jim,T.; Hicks, Michael W.; Wang, Y.; Cheney,J. (Computer Science Technical Reports, 2001)
The current version of this manual should be available at http://www.cs.cornell.edu/projects/cyclone/ and http://www.research.att.com/projects/cyclone/. The version here describes Cyclone Version 0.1.3, although minor changes may have occurred before the release.

Distributed processing of very large datasets with DataCutter - Beynon,Michael D.; Kurc,Tahsin; Catalyurek,Umit; Chang,Chialin; Sussman, Alan; Saltz,Joel (Parallel Computing, 2001)
We describe a framework, called DataCutter, that is designed to provide support for subsetting and processing of datasets in a distributed and heterogeneous environment. We illustrate the use of DataCutter with several data-intensive applications from diverse fields, and present experimental results.
Keywords: Component architectures; Data analysis; Distributed computing; Multi-dimensional datasets; Runtime systems

A dynamic replica selection algorithm for tolerating timing faults - Krishnamurthy, S.; Sanders,W. H.; Michel Cukier (2001)
Server replication is commonly used to improve the fault tolerance and response time of distributed services. An important problem when executing time-critical applications in a replicated environment is that of preventing timing failures by dynamically selecting the replicas that can satisfy a client's timing requirement, even when the quality of service is degraded due to replica failures and excess load on the server. We describe the approach we have used to solve this problem in AQuA, a CORBA-based middleware that transparently replicates objects across a local area network. The approach we use estimates a replica's response time distribution based on performance measurements regularly broadcast by the replica. An online model uses these measurements to predict the probability with which a replica can prevent a timing failure for a client. A selection algorithm then uses this prediction to choose a subset of replicas that can together meet the client's timing constraints with at least the probability requested by the client. We conclude with experimental results based on our implementation.
Keywords: AQuA; client; client-server systems; CORBA-based middleware; distributed object management; distributed services; dynamic replica selection algorithm; fault tolerant computing; local area network; Local area networks; quality of service; replica failures; response time; server replication; time-critical applications; timing failures; timing fault tolerance

Efficient Model Checking Via Buchi Tableau Automata⋆ - Bhat,G. S; Cleaveland, Rance; Groce,A. (Computer aided verification: 13th International conference, CAV 2001, Paris, France, July 18-22, 2001: proceedings, 2001)

Equivalence and preorder checking for finite-state systems - Cleaveland, Rance; Sokolsky,O. (Handbook of Process Algebra, 2001)

An experience management system for a software engineering research organization - Basili, Victor R.; Costa,P.; Lindvall,M.; Mendonca,M.; Seaman,C.; Tesoriero,R.; Zelkowitz, Marvin V (Software Engineering Workshop, 2001. Proceedings. 26th Annual NASA Goddard, 2001)
Most businesses rely on the fact that their employees possess relevant knowledge and that they can apply it to the task at hand. The problem is that this knowledge is not owned by the organization. It is owned and controlled by its employees. Maintaining an appropriate level of knowledge in the organization is a very important issue. It is, however, not an easy task for most organizations, and it is particularly problematic for software organizations, which are human- and knowledge-intensive. Knowledge management is a relatively new area that has attempted to address these problems. This paper introduces an approach called the "knowledge dust-to-pearls" approach. This approach addresses some of the issues with knowledge management by providing low-barrier mechanisms to "jump start" the experience base. This approach allows the experience base to become more useful more quickly than traditional approaches. This paper describes the approach and gives an example of its use at the Fraunhofer Center for Experimental Software Engineering, Maryland, USA
Keywords: and; approach; knowledge; base; experience; Center; control; knowledge; data; development; dust-to-pearls; engineering; Engineering; business; engineering; software; experimental; for; Fraunhofer; houses; knowledge; employee; knowledge; experience; level; maintenance; knowledge; management; management; knowledge; management; software; mechanisms; software; organization; software; organizational; organizations; administrative; organizations; knowledge; organizations; low-barrier; ownership; knowledge-intensive; processing; personnel; research; research; software; system; human-intensive

Experimental Analysis of Algorithms for Bilateral-Contract Clearing Mechanisms Arising in Deregulated Power Industry - Barrett,Chris; Cook,Doug; Hicks,Gregory; Faber,Vance; Marathe,Achla; Marathe,Madhav; Srinivasan, Aravind; Sussmann,Yoram; Thornquist,Heidi (Algorithm EngineeringAlgorithm Engineering, 2001)
We consider the bilateral contract satisfaction problem arising from electrical power networks due to the proposed deregulation of the electric utility industry in the USA. Given a network and a (multi)set of pairs of vertices (contracts) with associated demands, the goal is to find the maximum number of simultaneously satisfiable contracts. We study how four different algorithms perform in fairly realistic settings; we use an approximate electrical power network from Colorado. Our experiments show that three heuristics outperform a theoretically better algorithm. We also test the algorithms on four types of scenarios that are likely to occur in a deregulated marketplace. Our results show that the networks that are adequate in a regulated marketplace might be inadequate for satisfying all the bilateral contracts in a deregulated industry.

Handling uncertainty with active logic - Bhatia,M.; Chi,P.; Chong,W.; Josyula,D. P; Okamoto,Y.; Perlis, Don; Purang,K. (In Proceedings, AAAI Fall Symposium on Uncertainty in Computation, 2001)

Haptic and aural rendering of a virtual milling process - Chang,C. F; Varshney, Amitabh; Ge,Q. J (ASME 2001 Design Engineering Technical Conference and Computers and Information in Engineering Conference, Pittsburgh, PA, 2001)

Hierarchical image-based and polygon-based rendering for large-scale visualizations - Chang,C. F; Varshney, Amitabh; Ge,Q. J (Hierarchical and Geometrical Methods in Scientific VisualizationHierarchical and Geometrical Methods in Scientific Visualization, 2001)

A hypergraph-based workload partitioning strategy for parallel data aggregation - Chang,C.; Kurc, T.; Sussman, Alan; Catalyurek,U.; Saltz, J. (Proceedings of the Eleventh SIAM Conference on Parallel Processing for Scientific Computing, 2001)

Implementing the Experience Factory concepts as a set of Experience Bases - Basili, Victor R.; Lindvall,M.; Costa,P. (Proc. 13th Int’l Conf. Software Eng. and Knowledge Eng, 2001)
This talk takes the Experience Factory concept, which was originally developed as organizational support for softwaredevelopment and generalizes it to organizational support for any aspect of a business, e.g., business practices. The Experience Factory supports the evolution of processes and other forms of knowledge, based upon experiences within the organization, and related knowledge gathered from outside the organization. It then discusses how you might design an appropriate experience base for the particular set of organizational needs determined to be of importance. Specific examples are given in developing experience bases for specific organizations and it discusses the Experience Management System (EMS) currently being evolved and how it has been applied.

Integrated Microelectromechanical System (MEMS) Inertial Measurement Unit (IMIMU) - Fedder,Gary K.; Blanton,Shawn; Carley,L. R.; Gupta, Satyandra K.; Koester,David (CARNEGIE-MELLON UNIVERSITY, 2001)
Processes, designs and design tools are developed to enable the monolithic integration of arrays of inertial microsensors with electronics. Accelerometers and gyroscopes, fabricated in a single CMOS process, are functional and demonstrate a single chip IMU. Two integrated post CMOS micro-machining processes are demonstrated. Thin-film microstructures are defined from the metal-dielectric stack of a conventional process. In the second process, a back-side silicon etch, followed by front-side DRIE produces bulk silicon microstructures. Accelerometer and gyroscope designs are developed with accompanying low noise electronic circuitry. Noise performance was limited to 1/f circuit noise. The chip output sensibility is set by the interface circuit design. A thermally stabilized accelerometer and circuit design is demonstrated using embedded polysilicon resistors as temperature sensors and heaters in a closed loop. Nested gyroscope topologies are demonstrated with a lateral MEMS accelerometer used as a coriolis acceleration sensor. Modeling and simulation tools that simultaneously consider the electromechanical transducer and the electronic circuit to predict system performance are developed. Electrical, electromechanical and mechanical parasitics required to enable predictive lumped parameter simulation are identified and can be extracted, enabling a designer to confidently estimate design performance prior to fabrication. Generic physics-based fault models for surface-micromachined actuators and sensors are developed that enable effective testing, diagnosis and design for manufacturability.
Keywords: *ELECTROMECHANICAL DEVICES; *GYROSCOPES; *INERTIAL MEASUREMENT UNITS; *INERTIAL NAVIGATION; *MICROELECTROMECHANICAL SYSTEMS; ACCELEROMETERS; BULK MATERIALS; CHIPS(ELECTRONICS); CIRCUITS; CLOSED LOOP SYSTEMS; CORIOLIS EFFECT; Detectors; DIELECTRICS; ELECTRICAL AND ELECTRONIC EQUIPMENT; EMBEDDING; METALS; MICROSENSORS.; MICROSTRUCTURE; MONOLITHIC STRUCTURES(ELECTRONICS); NAVIGATION AND GUIDANCE; PARASITES; PE63739E; PERFORMANCE(ENGINEERING); POLYSILICONS; RESISTORS; SILICON; TEMPERATURE SENSITIVE ELEMENTS; THERMAL STABILITY; THIN FILMS; tools; Topology; WUAFRLE1170030

Intrusion tolerance approaches in ITUA - Michel Cukier; Lyons,J.; Pandey,P.; Ramasamy,H. V.; Sanders,W. H.; Pal,P.; Webber,F.; Schantz,R.; Loyall,J.; Watro,R. (2001)

Mandarin-English Information (MEI): investigating translingual speech retrieval - Meng,Helen; Chen,Berlin; Khudanpur,Sanjeev; Levow,Gina-Anne; Lo,Wai-Kit; Oard, Douglas; Schone,Patrick; Tang,Karen; Wang,Hsin-Min; Wang,Jianqiang (Proceedings of the first international conference on Human language technology research, 2001)
This paper describes the Mandarin-English Information (MEI) project, where we investigated the problem of cross-language spoken document retrieval (CL-SDR), and developed one of the first English-Chinese CL-SDR systems. Our system accepts an entire English news story (text) as query, and retrieves relevant Chinese broadcast news stories (audio) from the document collection. Hence this is a cross-language and cross-media retrieval task. We applied a multi-scale approach to our problem, which unifies the use of phrases, words and subwords in retrieval. The English queries are translated into Chinese by means of a dictionary-based approach, where we have integrated phrase-based translation with word-by-word translation. Untranslatable named entities are transliterated by a novel subword translation technique. The multi-scale approach can be divided into three subtasks -- multi-scale query formulation, multi-scale audio indexing (by speech recognition) and multi-scale retrieval. Experimental results demonstrate that the use of phrase-based translation and subword translation gave performance gains, and multi-scale retrieval outperforms word-based retrieval.
Keywords: cross-language; English-Chinese; spoken document retrieval

Performance optimization for data intensive grid applications - Beynon,M. D; Sussman, Alan; Catalyurek,U.; Kurc, T.; Saltz, J. (Active Middleware Services, 2001. Third Annual International Workshop on, 2001)

Reading between the lines: Lessons from the SDMI challenge - Craver,S.A.; Wu,M.; Liu,B.; Stubblefield,A.; Swartzlander,B.; Wallach,D.S.; Dean,D.; Felten,E.W. (Proceedings of the 10th USENIX Security Symposium, 2001)
The Secure Digital Music Initiative is a consortium ofparties interested in preventing piracy of digital music, and to this end they are developing architectures for con- tent protection on untrusted platforms. SDMI recently held a challenge to test the strength of four watermark- ing technologies, and two other security technologies. No documentation explained the implementations of the technologies, and neither watermark embedding nor de- tecting software was directly accessible to challenge par- ticipants. We nevertheless accepted the challenge, and explored the inner workings of the technologies. We re- port on our results here.

Relating amino acid sequence to phenotype: analysis of peptide-binding data - Segal,M. R; Cummings, Michael P.; Hubbard,A. E (Biometrics, 2001)
We illustrate data analytic concerns that arise in the context of relating genotype, as represented by amino acid sequence, to phenotypes (outcomes). The present application examines whether peptides that bind to a particular major histocompatibility complex (MHC) class I molecule have characteristic amino acid sequences. However, the concerns identified and addressed are considerably more general. It is recognized that simple rules for predicting binding based solely on preferences for specific amino acids in certain (anchor) positions of the peptide's amino acid sequence are generally inadequate and that binding is potentially influenced by all sequence positions as well as between-position interactions. The desire to elucidate these more complex prediction rules has spawned various modeling attempts, the shortcomings of which provide motivation for the methods adopted here. Because of (i) this need to model between-position interactions, (ii) amino acids constituting a highly (20) multilevel unordered categorical covariate, and (iii) there frequently being numerous such covariates (i.e., positions) comprising the sequence, standard regression/classification techniques are problematic due to the proliferation of indicator variables required for encoding the sequence position covariates and attendant interactions. These difficulties have led to analyses based on (continuous) properties (e.g., molecular weights) of the amino acids. However, there is potential information loss in such an approach if the properties used are incomplete and/or do not capture the mechanism underlying association with the phenotype. Here we demonstrate that handling unordered categorical covariates with numerous levels and accompanying interactions can be done effectively using classification trees and recently devised bump-hunting methods. We further tackle the question of whether observed associations are attributable to amino acid properties as well as addressing the assessment and implications of between-position covariation.

Rescuing a destabilized protein fold through backbone cyclization - Camarero,Julio A; Fushman, David; Sato,Satoshi; Giriat,Izabela; Cowburn,David; Raleigh,Daniel P; Muir,Tom W (Journal of Molecular Biology, 2001)
We describe the physicochemical characterization of various circular and linear forms of the ∼60 residue N-terminal Src homology 3 (SH3) domain from the murine c-Crk adapter protein. Structural, dynamic, thermodynamic, kinetic and biochemical studies reveal that backbone circularization does not prevent the adoption of the natural folded structure in any of the circular proteins. Both the folding and unfolding rate of the protein increased slightly upon circularization. Circularization did not lead to a significant thermodynamic stabilization of the full-length protein, suggesting that destabilizing enthalpic effects (e.g. strain) negate the expected favorable entropic contribution to overall stability. In contrast, we find circularization results in a dramatic stabilization of a truncated version of the SH3 domain lacking a key glutamate residue. The ability to rescue the destabilized mutant indicates that circularization may be a useful tool in protein engineering programs geared towards generating minimized proteins.
Keywords: circular protein; ligation; SH3 domain

The role of a natural language conversational interface in online sales: A case study - Chai,J.; Jimmy Lin; Zadrozny,W.; Ye,Y.; Stys-Budzikowska,M.; Horvath,V.; Kambhatla,N.; Wolf,C. (International Journal of Speech Technology, 2001)
This paper describes the evaluation of a natural language dialog-based navigation system (HappyAssistant) that helps users access e-commerce sites to find relevant information about products and services. The prototype system leverages technologies in natural language processing and human-computer interaction to create a faster and more intuitive way of interacting with websites, especially for less experienced users. The result of a comparative study shows that users prefer the natural language-enabled navigation two to one over the menu driven navigation. In addition, the study confirmed the efficiency of using natural language dialog in terms of the number of clicks and the amount of time required to obtain the relevant information. In the case study, as compared to the menu driven system, the average number of clicks used in the natural language system was reduced by 63.2% and the average time was reduced by 33.3%.

Rotation, scale, and translation resilient public watermarking for images using a log-polar fourier transform - Bloom,Jeffrey A.; Cox,Ingemar J.; Miller,Matthew L.; M. Wu; Lin,Ching-Yung; Lui,Yui Man (2001)
A method for detecting a watermark signal in digital image data. The detecting method includes the steps of: computing a log-polar Fourier transform of the image data to obtain a log-polar Fourier spectrum; projecting the log-polar Fourier spectrum down to a lower dimensional space to obtain an extracted signal; comparing the extracted signal to a target watermark signal; and declaring the presence or absence of the target watermark signal in the image data based on the comparison. Also provided is a method for inserting a watermark signal in digital image data to obtain a watermarked image. The inserting method includes the steps of: computing a log-polar Fourier transform of the image data to obtain a log-polar Fourier spectrum; projecting the log-polar Fourier spectrum down to a lower dimensional space to obtain an extracted signal; modifying the extracted signal such that it is similar to a target watermark; performing a one-to-many mapping of the modified signal back to...

Rotation, scale, and translation resilient watermarking for images - Lin,C.-Y.; Wu,M.; Bloom,J.A.; Cox,I.J.; Miller,M.L.; Lui,Y.M. (Image Processing, IEEE Transactions on, 2001)
Many electronic watermarks for still images and video content are sensitive to geometric distortions. For example, simple rotation, scaling, and/or translation (RST) of an image can prevent blind detection of a public watermark. In this paper, we propose a watermarking algorithm that is robust to RST distortions. The watermark is embedded into a one-dimensional (1-D) signal obtained by taking the Fourier transform of the image, resampling the Fourier magnitudes into log-polar coordinates, and then summing a function of those magnitudes along the log-radius axis. Rotation of the image results in a cyclical shift of the extracted signal. Scaling of the image results in amplification of the extracted signal, and translation of the image has no effect on the extracted signal. We can therefore compensate for rotation with a simple search, and compensate for scaling by using the correlation coefficient as the detection measure. False positive results on a database of 10 000 images are reported. Robustness results on a database of 2000 images are described. It is shown that the watermark is robust to rotation, scale, and translation. In addition, we describe tests examining the watermarks resistance to cropping and JPEG compression
Keywords: axis; one-dimensional; coding; security; coefficient; cropping; cyclical; compression; RST; coordinates; log-radius; data; detection; correlation; distortions; blind; distortions; images; log-polar; encapsulation; image; Fourier; images; translation; magnitudes; Fourier; measure; geometric; of; protection; data; resilient; shift; detection; signal; public; transform; JPEG; transforms; copy; watermark; resampling; rotation; scale; search; still; watermarking; video; Fourier

Safe and Flexible Dynamic Linking of Native Code - Hicks, Michael W.; Weirich,Stephanie; Crary,Karl (Types in Compilation, 2001)
We present the design and implementation of the first complete framework for flexible and safe dynamic linking of native code. Our approach extends Typed Assembly Language with a primitive for loading and typechecking code, which is flexible enough to support a variety of linking strategies, but simple enough that it does not significantly expand the trusted computing base. Using this primitive, along with the ability to compute with types, we show that we can program many existing dynamic linking approaches. As a concrete demonstration, we have used our framework to implement dynamic linking for a type-safe dialect of C, closely modeled after the standard linking facility for Unix C programs. Aside from the unavoidable cost of verification, our implementation performs comparably with the standard, untyped approach.

Simulation revisited - Tan,L.; Cleaveland, Rance (Tools and Algorithms for the Construction and Analysis of Systems, 2001)

Spanish Language Processing at University of Maryland: Building Infrastructure for Multilingual Applications - Cabezas,C.; Dorr, Bonnie J; Resnik, Philip (Instititue for Advanced Computer Studies, Univ of Maryland, College Park, 2001)
We describe here our construction of lexical resources, tool creation, building of an alignedparallel corpus, and an approach to automatic treebank creation that we have been de- veloping using Spanish data, based on projection of English syntactic dependency infor- mation across a parallel corpus.

Supervised sense tagging using support vector machines - Cabezas,C.; Resnik, Philip; Stevens,J. (Proceedings of the Second International Workshop on Evaluating Word Sense Disambiguation Systems (SENSEVAL-2), 2001)

Understanding Manufacturing Systems with a Learning Historian for User-Directed Experimentation - Chipman,G.; Plaisant, Catherine; Gahagan,S.; Herrmann,J.W.; Hewitt,S.; Reaves,L. (Department of Computer Science, University of Maryland, College Park, 2001)
This paper describes a learning historian to improve user-directed experimentation withdiscrete event simulation models of manufacturing systems. In user-directed experimentation, an analyst conducts simulation runs to estimate system performance. Then the analyst modifies the simulation model to evaluate other possibilities. An important characteristic is the ad hoc nature of the experimentation, as the analyst forms and runs new trials based on the results from previous trials. Through user-directed experimentation designers compare alternatives and students learn the relationships between input parameters and performance measures. Recording and reviewing previous trials while using simulation models enhances their benefits, transforming trial-and-error into learning. The learning historian combines a graphical user interface, a discrete event simulation model, and dynamic data visualization. Usability studies indicate that the learning historian is a usable and useful tool because it allows users to concentrate more on understanding system behavior than on operating simulation software.

Visualization of large data sets with the Active Data Repository - Kurc, T.; Catalyurek,U.; Chang,Chialin; Sussman, Alan; Saltz, J. (IEEE Computer Graphics and Applications, 2001)
We implement ray-casting-based volume rendering and isosurface rendering methods using the Active Data Repository (ADR) for visualizing out-of-core data sets. We have developed the ADR object-oriented framework to provide support for applications that employ range queries with user-defined mapping and aggregation operations on large-scale multidimensional data. ADR targets distributed-memory parallel machines with one or more disks attached to each node. It is designed as a set of modular services implemented in C++, which can be customized for application-specific processing. The ADR runtime system supports common operations such as memory management, data retrieval, and scheduling of processing across a parallel machine
Keywords: active data repository; ADR runtime system; Algorithm design and analysis; application-specific processing; C++; data mining; data retrieval; data visualisation; Data visualization; distributed-memory parallel machines; Indexing; Information retrieval; isosurface rendering; Isosurfaces; large data sets; large-scale multidimensional data; Memory management; modular services; out-of-core data sets; parallel machine; Parallel machines; Partitioning algorithms; ray-casting-based volume rendering; Rendering (computer graphics); Runtime; software libraries; storage management

What can we reasonably expect from watermarks? - Craver,S.A.; M. Wu; Liu,B. (Applications of Signal Processing to Audio and Acoustics, 2001 IEEE Workshop on the, 2001)
Digital watermarking has been positioned as a solution to copyright protection of digital music, and some doubt exists about its ability to perform in this regard. A survey of watermarking applications assesses the technology's potential for copy protection, as well as other digital audio applications
Keywords: applications; audio; applications; digital; audio; coding; copy; data; databases; music; hashing; steganography; watermarking; music; digital; of; protection; copyright; protection; copyright; music; security; protection; digital; watermarking; copy; watermarking; forensic; watermarking; music

Adaptive query processing: Technology in evolution - Hellerstein,J. M; Franklin,M.J.; Chandrasekaran,S.; Deshpande, Amol; Hildrum,K.; Madden,S.; Raman,V.; Shah,M. A (IEEE Data Engineering Bulletin, 2000)
As query engines are scaled and federated, they must cope with highly unpredictable and changeableenvironments. In the Telegraph project, we are attempting to architect and implement a continuously adaptive query engine suitable for global-area systems, massive parallelism, and sensor networks. To set the stage for our research, we present a survey of prior work on adaptive query processing, focusing on three characterizations of adaptivity: the frequency of adaptivity, the effects of adaptivity, and the extent of adaptivity. Given this survey, we sketch directions for research in the Telegraph project.

Assessment of Temperature Fluctuation Models for RANS Simulations of Hypersonic Reacting Flows - Sinha,K.; Martin, M.P; Candler,G. V (38th AIAA Aerospace Sciences Meeting and Exhibit, 2000)
Turbulence-chemistry interactions play an important role in various fluid flow problems. In a hypersonic boundary layer, these interactions can alter the surface heating rate of the vehicle by modifying the temperature profile across the layer. The effect of these interactions is accounted for in a Reynolds-averaged Navier Stokes (RANS) simulation using a probability density function (PDF) of the temperature distribution. In this paper, two presumed PDF models are considered, namely, the Martin and Candler model and the Gaffney et al. model, and their accuracy is assessed by comparing to direct numerical simulation (DNS) of homogeneous isotropic turbulence. TheMartin and Candler model reproduces the turbulence-chemistry interactions in the flow correctly whereas the Gaffney model overpredicts the temperature fluctuations.

A Case for Evolutionary Genomics and the Comprehensive Examination of Sequence Biodiversity - Pollock,David D; Eisen,Jonathan A.; Doggett,Norman A; Cummings, Michael P. (Molecular Biology and EvolutionMol Biol Evol, 2000)
Comparative analysis is one of the most powerful methods available for understanding the diverse and complex systems found in biology, but it is often limited by a lack of comprehensive taxonomic sampling. Despite the recent development of powerful genome technologies capable of producing sequence data in large quantities (witness the recently completed first draft of the human genome), there has been relatively little change in how evolutionary studies are conducted. The application of genomic methods to evolutionary biology is a challenge, in part because gene segments from different organisms are manipulated separately, requiring individual purification, cloning, and sequencing. We suggest that a feasible approach to collecting genome-scale data sets for evolutionary biology (i.e., evolutionary genomics) may consist of combination of DNA samples prior to cloning and sequencing, followed by computational reconstruction of the original sequences. This approach will allow the full benefit of automated protocols developed by genome projects to be realized; taxon sampling levels can easily increase to thousands for targeted genomes and genomic regions. Sequence diversity at this level will dramatically improve the quality and accuracy of phylogenetic inference, as well as the accuracy and resolution of comparative evolutionary studies. In particular, it will be possible to make accurate estimates of normal evolution in the context of constant structural and functional constraints (i.e., site-specific substitution probabilities), along with accurate estimates of changes in evolutionary patterns, including pairwise coevolution between sites, adaptive bursts, and changes in selective constraints. These estimates can then be used to understand and predict the effects of protein structure and function on sequence evolution and to predict unknown details of protein structure, function, and functional divergence. In order to demonstrate the practicality of these ideas and the potential benefit for functional genomic analysis, we describe a pilot project we are conducting to simultaneously sequence large numbers of vertebrate mitochondrial genomes.

Chromosome Identification Using Hidden Markov Models: Comparison with Neural Networks, Singular Value Decomposition, Principal Components Analysis, and Fisher Discriminant Analysis - Conroy,John M.; Kolda,Tamara G.; O'Leary, Dianne P.; O'Leary,Timothy J (Laboratory Investigation, 2000)
The analysis of G-banded chromosomes remains the most important tool available to the clinical cytogeneticist. The analysis is laborious when performed manually, and the utility of automated chromosome identification algorithms has been limited by the fact that classification accuracy of these methods seldom exceeds about 80% in routine practice. In this study, we use four new approaches to automated chromosome identification — singular value decomposition (SVD), principal components analysis (PCA), Fisher discriminant analysis (FDA), and hidden Markov models (HMM) — to classify three well-known chromosome data sets (Philadelphia, Edinburgh, and Copenhagen), comparing these approaches with the use of neural networks (NN). We show that the HMM is a particularly robust approach to identification that attains classification accuracies of up to 97% for normal chromosomes and retains classification accuracies of up to 95% when chromosome telomeres are truncated or small portions of the chromosome are inverted. This represents a substantial improvement of the classification accuracy for normal chromosomes, and a doubling in classification accuracy for truncated chromosomes and those with inversions, as compared with NN-based methods. HMMs thus appear to be a promising approach for the automated identification of both normal and abnormal G-banded chromosomes.
Keywords: addiction disorders; anxiety; depression; psychopharmacology; schizophrenia

Combinatorial Problems Arising in Deregulated Electrical Power Industry: Survey and Future Directions - Cook,D.; Hicks,G.; Faber,V.; Marathe,M. V; Srinivasan, Aravind; Sussmann,Y. J; Thornquist,H. (NONCONVEX OPTIMIZATION AND ITS APPLICATIONS, 2000)

Communication complexity of document exchange - Cormode,Graham; Paterson,Mike; Sahinalp,Süleyman Cenk; Vishkin, Uzi (Proceedings of the eleventh annual ACM-SIAM symposium on Discrete algorithms, 2000)

Comparative Evaluation of a Natural Language Dialog Based System and a Menu-Driven System for Information Access: A Case Study - Chai,J.; Jimmy Lin; Zadrozny,W.; Ye,Y.; Budzikowska,M.; Horvath,V.; Kambhatla,N.; Wolf,C. (In Proceedings of the International Conference on Multimedia Information Retrieval (RIAO 2000), 2000)
This paper describes the evaluation of a natural language dialog based navigation system (HappyAssistant) thathelps users access e-commerce sites to find relevant information about products and services. The prototype system leverages technologies in natural language processing and human computer interaction to create a faster and more intuitive way of interacting with websites, especially for the less experienced users. The result of a comparative study shows that users prefer the natural language enabled navigation two to one over the menu driven navigation. In addition, the study confirmed the efficiency of using natural language dialog in terms of the number of clicks and the amount of time required to obtain the relevant information. In the case study, comparing to the menu driven system, the average number of clicks used in the natural language system was reduced by 63.2% and the average time was reduced by 33.3%.

A comparison of voice controlled and mouse controlled web browsing - Christian,Kevin; Kules,Bill; Shneiderman, Ben; Youssef,Adel (Proceedings of the fourth international ACM conference on Assistive technologies, 2000)
Keywords: human-computer; interaction; User interfaces; voice browsers; voice recognition; web browsing

A compositional approach to statecharts semantics - L\üttgen,G.; Von Der Beeck,M.; Cleaveland, Rance (ACM, 2000)